64 3 sp to 77 4/OD Installation

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Slim Flipmin

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Ok, Moparians I am having a friend help me with installing a 77 "Feather" Duster 4 speed(yes, I know it's a 3 sp w OD) into my 64 column shift 3 sp Valiant. I have been told it will work. I have a clutch kit, floor hump from Brewers. I started cutting out the floor section and have a few questions.

1) If my measurements are correct the original driveshaft will be too long?
2)Does anyone know if the spline count is the same on the tail shaft(26 spline on the 77).
3)Will the clutch fork from the 64 work?
4) will I be able to clear the frame support that runs over the trans. or does it need to be trimmed.
5)Will the new trans. bolt up to the old support or is there a kit?
6) What else am I missing?

Thanks in advance if you need pics let me know I'm going out to take some now.
 
yes the retainer hole in the bell for the 833 OD is larger. I am not if the length of both trans are the same. might have to cut and weld the Z bar some. not big deal if so.
 
A 64 has a trunnion type drive shaft and a 77 trans obviously has the slip spline style. Unless you have a matching driveshaft that will be a problem.

It clears the t-bar/trans mount crossmember Ok.

You need the OD clutch fork that matches the OD bellhousing. You need the OD bell as the trans bolt pattern is different than the early 3 speed trans.

The rubber mount should bolt to the trsns mount no problem.
 
A 64 has a trunnion type drive shaft and a 77 trans obviously has the slip spline style. Unless you have a matching driveshaft that will be a problem.

It clears the t-bar/trans mount crossmember Ok.

You need the OD clutch fork that matches the OD bellhousing. You need the OD bell as the trans bolt pattern is different than the early 3 speed trans.

The rubber mount should bolt to the trsns mount no problem.
I have the bellhousing. So, I need to find a clutch fork and sort out the driveshaft. It sounds like otherwise I'll be in good shape?
 
As to the floorhump;
You didn't mention cutting open the tunnel to access the shifter and rods. Is your tunnel already so modified?
What is your plan for the shifter?
The fork has it's own pivot bracket. It may or may not put the fork in the right spot to hook up with the Zbar, in a straight push arrangement. You are the trailblazer.

I assume this project is to reduce your rpm at hiway speed, and or to try and get some better fuel mileage.
I'm not sure which box you might currently have, but Ima guessing it is the A903.
This box comes in a few flavors, but again, I'm guessing it is for a 170 under the hood.
This would have the following ratios; 3.22-1.84-1.00 with split %s of 57 and 54.6 This means that at whatever rpm you rev to before the shift, then after the shift the rpm will be at those percents. Example; if you outshift at 2800rpm, then the Rs will drop to 1599, and 1529.
With the A833od, the ratios are 3.09-1.67-1.00-.73 and the split %s are 54-60-73. Outshifting again at 2800, means the next gears come in at; 1512,1652,and 2044
That doesn't sound too bad, until you translate that to a roadspeed
Say you have 3.21s
Shifting at 2800;With your current tranny, will be about(25.5tires);21,36,and topped out @66mph=2800rpm.
Shifting at 2800;With the od tranny;21,40,66, now reving 2044 in od. The question is; will your 170 make enough power on the low-speed circuit to pull that? If it gets up on the mains, you may actually get less gas mileage. Also on the mains, the manifold vacuum will drop, and this may kill the vacuum advance. Between those two, the mileage will drop for sure.
I can see no other good reason to make this swap; except reduced rpm, or the allure of better fuel mileage.
>If the engine is in real good shape, it might have to potential to make 120 ftlbs at 2800. This is 64hp. Your car might require 40hp to maintain 66 mph. So with the current tranny, you might already require 78% of the available power.
With the A833 and the reduced to 2044rpm, your maximum torque might be reduced to say 70% of peak. This would be 84 ftlbs,or 33hp. If your car requires 40hp you're just not gonna be able to pull it with 3.21s.
All numbers as to torque and horsepower are best guesses on my part, and intended only for illustrative purposes.
If in fact you come up 7 hp short, this is a 17.5% shortfall using WOT. Increasing your rear gear that same 17.5%, might get your Rs up high enough to make it. That would then be 3.73s gears. Keep in mind that I may have underestimated the torque of the mighty 170. As it here stands, the 170 barely has enough torque at 2800 to maintain 66mph at 78% of full power. This is already waaay past the mains. I cannot imagine it will be able to maintain 66 at WOT with the overdrive.
But if you have a bigger engine, then this math falls apart. I just hate to see you go thru all this trouble and be disappointed.

Here is an experiment for you; load the car up with about 300 extra pounds, and find a hill with a long enough level approach to get her up to a cruising speed of 48mph (73% of 66 mph;to simulate the od box),and head for that hill.As the car begins the ascent it will slow down. Keep giving her gas, until she is able to maintain the climb at that 48mph. If she can't do it, you are probably screwed. If you end up using more than 50% throttle, you will lose gas mileage with the overdrive. I used the extra pounds so simulate the wind-resistance from 48 to 66mph, and guessed at the amount of weight to add. The grade of the hill is to illustrate the reserve power, at 2044rpm with 3.21s.If you have different gears, the experiment would need to be amended.
>If you have a vacuum gauge, put that on manifold vacuum, and put it somewhere you can see it during the test.If the manifold vacuum at any time,falls to under 12 inches then the carb is already open past the transfers, (where the economy is). If it falls to under about 10 inches, then you are deep into the mains. By 8 inches you are well into the power valve system, and of course the vacuum advance is long g-o-n-e,gone.You are sucking gas big time.
 
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Wow AJ, you threw a wet blanket on this one. Slim didn't say what
mill he's running. If he's got his stuff together, I say go for it.

I also have a 64 Valiant with the optional "big" 225. I just rebuilt it and got it running last fall. It's 3 on the tree with the standard 3.23 gear. I put about 400 miles on it before winter and it seems to have plenty of power. I will say the column shift sucks. Even with careful slow granny shifting it tends to jam and I have to pull over and unjam it. I'm going to give it another try because I just bought some new shifter bushings that will enable me to get a more precise adjustment.

But....I've been collecting parts for a 4 speed conversion. As luck would have it, I now have both a 65 4 speed trunnion mount trans with Hurst shifter and a mid 70's OD trans with shifter and the Bellhousings for both. I finally also obtained 2 floor humps. One is a 64-65 round hole and the other is a 66 oblong hole. The earlier one is VERY rusty but has the correct shifter hole. The 66 is much better but has incorrect hole.

My plan is to try the 65 trans first as my trunnion driveshaft is in good shape and is a direct bolt-in. The OD would require a new shaft. I'll probably try both eventually just for fun. This car will be a driver (entered in this year's Carlisle) and I'd like to get decent mileage so it'll be interesting.
 
As to the floorhump;
You didn't mention cutting open the tunnel to access the shifter and rods. Is your tunnel already so modified?
What is your plan for the shifter?
The fork has it's own pivot bracket. It may or may not put the fork in the right spot to hook up with the Zbar, in a straight push arrangement. You are the trailblazer.

I assume this project is to reduce your rpm at hiway speed, and or to try and get some better fuel mileage.
I'm not sure which box you might currently have, but Ima guessing it is the A903.
This box comes in a few flavors, but again, I'm guessing it is for a 170 under the hood.
This would have the following ratios; 3.22-1.84-1.00 with split %s of 57 and 54.6 This means that at whatever rpm you rev to before the shift, then after the shift the rpm will be at those percents. Example; if you outshift at 2800rpm, then the Rs will drop to 1599, and 1529.
With the A833od, the ratios are 3.09-1.67-1.00-.73 and the split %s are 54-60-73. Outshifting again at 2800, means the next gears come in at; 1512,1652,and 2044
That doesn't sound too bad, until you translate that to a roadspeed
Say you have 3.21s
Shifting at 2800;With your current tranny, will be about(25.5tires);21,36,and topped out @66mph=2800rpm.
Shifting at 2800;With the od tranny;21,40,66, now reving 2044 in od. The question is; will your 170 make enough power on the low-speed circuit to pull that? If it gets up on the mains, you may actually get less gas mileage. Also on the mains, the manifold vacuum will drop, and this may kill the vacuum advance. Between those two, the mileage will drop for sure.
I can see no other good reason to make this swap; except reduced rpm, or the allure of better fuel mileage.
>If the engine is in real good shape, it might have to potential to make 120 ftlbs at 2800. This is 64hp. Your car might require 40hp to maintain 66 mph. So with the current tranny, you might already require 78% of the available power.
With the A833 and the reduced to 2044rpm, your maximum torque might be reduced to say 70% of peak. This would be 84 ftlbs,or 33hp. If your car requires 40hp you're just not gonna be able to pull it with 3.21s.
All numbers as to torque and horsepower are best guesses on my part, and intended only for illustrative purposes.
If in fact you come up 7 hp short, this is a 17.5% shortfall using WOT. Increasing your rear gear that same 17.5%, might get your Rs up high enough to make it. That would then be 3.73s gears. Keep in mind that I may have underestimated the torque of the mighty 170. As it here stands, the 170 barely has enough torque at 2800 to maintain 66mph at 78% of full power. This is already waaay past the mains. I cannot imagine it will be able to maintain 66 at WOT with the overdrive.
But if you have a bigger engine, then this math falls apart. I just hate to see you go thru all this trouble and be disappointed.

Here is an experiment for you; load the car up with about 300 extra pounds, and find a hill with a long enough level approach to get her up to a cruising speed of 48mph (73% of 66 mph;to simulate the od box),and head for that hill.As the car begins the ascent it will slow down. Keep giving her gas, until she is able to maintain the climb at that 48mph. If she can't do it, you are probably screwed. If you end up using more than 50% throttle, you will lose gas mileage with the overdrive. I used the extra pounds so simulate the wind-resistance from 48 to 66mph, and guessed at the amount of weight to add. The grade of the hill is to illustrate the reserve power, at 2044rpm with 3.21s.If you have different gears, the experiment would need to be amended.
>If you have a vacuum gauge, put that on manifold vacuum, and put it somewhere you can see it during the test.If the manifold vacuum at any time,falls to under 12 inches then the carb is already open past the transfers, (where the economy is). If it falls to under about 10 inches, then you are deep into the mains. By 8 inches you are well into the power valve system, and of course the vacuum advance is long g-o-n-e,gone.You are sucking gas big time.[/QU
As to the floorhump;
You didn't mention cutting open the tunnel to access the shifter and rods. Is your tunnel already so modified?
What is your plan for the shifter?
The fork has it's own pivot bracket. It may or may not put the fork in the right spot to hook up with the Zbar, in a straight push arrangement. You are the trailblazer.

I assume this project is to reduce your rpm at hiway speed, and or to try and get some better fuel mileage.
I'm not sure which box you might currently have, but Ima guessing it is the A903.
This box comes in a few flavors, but again, I'm guessing it is for a 170 under the hood.
This would have the following ratios; 3.22-1.84-1.00 with split %s of 57 and 54.6 This means that at whatever rpm you rev to before the shift, then after the shift the rpm will be at those percents. Example; if you outshift at 2800rpm, then the Rs will drop to 1599, and 1529.
With the A833od, the ratios are 3.09-1.67-1.00-.73 and the split %s are 54-60-73. Outshifting again at 2800, means the next gears come in at; 1512,1652,and 2044
That doesn't sound too bad, until you translate that to a roadspeed
Say you have 3.21s
Shifting at 2800;With your current tranny, will be about(25.5tires);21,36,and topped out @66mph=2800rpm.
Shifting at 2800;With the od tranny;21,40,66, now reving 2044 in od. The question is; will your 170 make enough power on the low-speed circuit to pull that? If it gets up on the mains, you may actually get less gas mileage. Also on the mains, the manifold vacuum will drop, and this may kill the vacuum advance. Between those two, the mileage will drop for sure.
I can see no other good reason to make this swap; except reduced rpm, or the allure of better fuel mileage.
>If the engine is in real good shape, it might have to potential to make 120 ftlbs at 2800. This is 64hp. Your car might require 40hp to maintain 66 mph. So with the current tranny, you might already require 78% of the available power.
With the A833 and the reduced to 2044rpm, your maximum torque might be reduced to say 70% of peak. This would be 84 ftlbs,or 33hp. If your car requires 40hp you're just not gonna be able to pull it with 3.21s.
All numbers as to torque and horsepower are best guesses on my part, and intended only for illustrative purposes.
If in fact you come up 7 hp short, this is a 17.5% shortfall using WOT. Increasing your rear gear that same 17.5%, might get your Rs up high enough to make it. That would then be 3.73s gears. Keep in mind that I may have underestimated the torque of the mighty 170. As it here stands, the 170 barely has enough torque at 2800 to maintain 66mph at 78% of full power. This is already waaay past the mains. I cannot imagine it will be able to maintain 66 at WOT with the overdrive.
But if you have a bigger engine, then this math falls apart. I just hate to see you go thru all this trouble and be disappointed.

Here is an experiment for you; load the car up with about 300 extra pounds, and find a hill with a long enough level approach to get her up to a cruising speed of 48mph (73% of 66 mph;to simulate the od box),and head for that hill.As the car begins the ascent it will slow down. Keep giving her gas, until she is able to maintain the climb at that 48mph. If she can't do it, you are probably screwed. If you end up using more than 50% throttle, you will lose gas mileage with the overdrive. I used the extra pounds so simulate the wind-resistance from 48 to 66mph, and guessed at the amount of weight to add. The grade of the hill is to illustrate the reserve power, at 2044rpm with 3.21s.If you have different gears, the experiment would need to be amended.
>If you have a vacuum gauge, put that on manifold vacuum, and put it somewhere you can see it during the test.If the manifold vacuum at any time,falls to under 12 inches then the carb is already open past the transfers, (where the economy is). If it falls to under about 10 inches, then you are deep into the mains. By 8 inches you are well into the power valve system, and of course the vacuum advance is long g-o-n-e,gone.You are sucking gas big time.
As to the floorhump;
You didn't mention cutting open the tunnel to access the shifter and rods. Is your tunnel already so modified?
What is your plan for the shifter?
The fork has it's own pivot bracket. It may or may not put the fork in the right spot to hook up with the Zbar, in a straight push arrangement. You are the trailblazer.

I assume this project is to reduce your rpm at hiway speed, and or to try and get some better fuel mileage.
I'm not sure which box you might currently have, but Ima guessing it is the A903.
This box comes in a few flavors, but again, I'm guessing it is for a 170 under the hood.
This would have the following ratios; 3.22-1.84-1.00 with split %s of 57 and 54.6 This means that at whatever rpm you rev to before the shift, then after the shift the rpm will be at those percents. Example; if you outshift at 2800rpm, then the Rs will drop to 1599, and 1529.
With the A833od, the ratios are 3.09-1.67-1.00-.73 and the split %s are 54-60-73. Outshifting again at 2800, means the next gears come in at; 1512,1652,and 2044
That doesn't sound too bad, until you translate that to a roadspeed
Say you have 3.21s
Shifting at 2800;With your current tranny, will be about(25.5tires);21,36,and topped out @66mph=2800rpm.
Shifting at 2800;With the od tranny;21,40,66, now reving 2044 in od. The question is; will your 170 make enough power on the low-speed circuit to pull that? If it gets up on the mains, you may actually get less gas mileage. Also on the mains, the manifold vacuum will drop, and this may kill the vacuum advance. Between those two, the mileage will drop for sure.
I can see no other good reason to make this swap; except reduced rpm, or the allure of better fuel mileage.
>If the engine is in real good shape, it might have to potential to make 120 ftlbs at 2800. This is 64hp. Your car might require 40hp to maintain 66 mph. So with the current tranny, you might already require 78% of the available power.
With the A833 and the reduced to 2044rpm, your maximum torque might be reduced to say 70% of peak. This would be 84 ftlbs,or 33hp. If your car requires 40hp you're just not gonna be able to pull it with 3.21s.
All numbers as to torque and horsepower are best guesses on my part, and intended only for illustrative purposes.
If in fact you come up 7 hp short, this is a 17.5% shortfall using WOT. Increasing your rear gear that same 17.5%, might get your Rs up high enough to make it. That would then be 3.73s gears. Keep in mind that I may have underestimated the torque of the mighty 170. As it here stands, the 170 barely has enough torque at 2800 to maintain 66mph at 78% of full power. This is already waaay past the mains. I cannot imagine it will be able to maintain 66 at WOT with the overdrive.
But if you have a bigger engine, then this math falls apart. I just hate to see you go thru all this trouble and be disappointed.

Here is an experiment for you; load the car up with about 300 extra pounds, and find a hill with a long enough level approach to get her up to a cruising speed of 48mph (73% of 66 mph;to simulate the od box),and head for that hill.As the car begins the ascent it will slow down. Keep giving her gas, until she is able to maintain the climb at that 48mph. If she can't do it, you are probably screwed. If you end up using more than 50% throttle, you will lose gas mileage with the overdrive. I used the extra pounds so simulate the wind-resistance from 48 to 66mph, and guessed at the amount of weight to add. The grade of the hill is to illustrate the reserve power, at 2044rpm with 3.21s.If you have different gears, the experiment would need to be amended.
>If you have a vacuum gauge, put that on manifold vacuum, and put it somewhere you can see it during the test.If the manifold vacuum at any time,falls to under 12 inches then the carb is already open past the transfers, (where the economy is). If it falls to under about 10 inches, then you are deep into the mains. By 8 inches you are well into the power valve system, and of course the vacuum advance is long g-o-n-e,gone.You are sucking gas big time.
As to the floorhump;
You didn't mention cutting open the tunnel to access the shifter and rods. Is your tunnel already so modified?
What is your plan for the shifter?
The fork has it's own pivot bracket. It may or may not put the fork in the right spot to hook up with the Zbar, in a straight push arrangement. You are the trailblazer.

I assume this project is to reduce your rpm at hiway speed, and or to try and get some better fuel mileage.
I'm not sure which box you might currently have, but Ima guessing it is the A903.
This box comes in a few flavors, but again, I'm guessing it is for a 170 under the hood.
This would have the following ratios; 3.22-1.84-1.00 with split %s of 57 and 54.6 This means that at whatever rpm you rev to before the shift, then after the shift the rpm will be at those percents. Example; if you outshift at 2800rpm, then the Rs will drop to 1599, and 1529.
With the A833od, the ratios are 3.09-1.67-1.00-.73 and the split %s are 54-60-73. Outshifting again at 2800, means the next gears come in at; 1512,1652,and 2044
That doesn't sound too bad, until you translate that to a roadspeed
Say you have 3.21s
Shifting at 2800;With your current tranny, will be about(25.5tires);21,36,and topped out @66mph=2800rpm.
Shifting at 2800;With the od tranny;21,40,66, now reving 2044 in od. The question is; will your 170 make enough power on the low-speed circuit to pull that? If it gets up on the mains, you may actually get less gas mileage. Also on the mains, the manifold vacuum will drop, and this may kill the vacuum advance. Between those two, the mileage will drop for sure.
I can see no other good reason to make this swap; except reduced rpm, or the allure of better fuel mileage.
>If the engine is in real good shape, it might have to potential to make 120 ftlbs at 2800. This is 64hp. Your car might require 40hp to maintain 66 mph. So with the current tranny, you might already require 78% of the available power.
With the A833 and the reduced to 2044rpm, your maximum torque might be reduced to say 70% of peak. This would be 84 ftlbs,or 33hp. If your car requires 40hp you're just not gonna be able to pull it with 3.21s.
All numbers as to torque and horsepower are best guesses on my part, and intended only for illustrative purposes.
If in fact you come up 7 hp short, this is a 17.5% shortfall using WOT. Increasing your rear gear that same 17.5%, might get your Rs up high enough to make it. That would then be 3.73s gears. Keep in mind that I may have underestimated the torque of the mighty 170. As it here stands, the 170 barely has enough torque at 2800 to maintain 66mph at 78% of full power. This is already waaay past the mains. I cannot imagine it will be able to maintain 66 at WOT with the overdrive.
But if you have a bigger engine, then this math falls apart. I just hate to see you go thru all this trouble and be disappointed.

Here is an experiment for you; load the car up with about 300 extra pounds, and find a hill with a long enough level approach to get her up to a cruising speed of 48mph (73% of 66 mph;to simulate the od box),and head for that hill.As the car begins the ascent it will slow down. Keep giving her gas, until she is able to maintain the climb at that 48mph. If she can't do it, you are probably screwed. If you end up using more than 50% throttle, you will lose gas mileage with the overdrive. I used the extra pounds so simulate the wind-resistance from 48 to 66mph, and guessed at the amount of weight to add. The grade of the hill is to illustrate the reserve power, at 2044rpm with 3.21s.If you have different gears, the experiment would need to be amended.
>If you have a vacuum gauge, put that on manifold vacuum, and put it somewhere you can see it during the test.If the manifold vacuum at any time,falls to under 12 inches then the carb is already open past the transfers, (where the economy is). If it falls to under about 10 inches, then you are deep into the mains. By 8 inches you are well into the power valve system, and of course the vacuum advance is long g-o-n-e,gone.You are sucking gas big time.
I'm running 225 with 46,*** original miles. I have the tunnel cut out and prepped. Didn't some of the 77 Dusters also come with the slant 6? I thought the whole point of the aluminum body transmissions were efforts to make the cars more economical once the gas crisis hit in the 70's. I really just want to get rid of the column shift. Maybe I should just scrap it and go with a Toyota 5 speed gearbox....I hear the Aussies have an adapter for that.
 
76 feather duster. I had one that came with an auto but generally were 833 OD yes alum case does help weight,too, as the feather duster had some aluminum parts to help weight. the super six of that time was a 225 with 2 bbl
I understand A/JFormS comment bout the OD as related to power of the a 170 slant, which my 62 lancer has but I also have a 833 and a 3 speed out of 72 duster I can use, the 3 on tree does not remind me of my childhood so it will GO away.
 
I'm running 225 with 46,*** original miles. I have the tunnel cut out and prepped. Didn't some of the 77 Dusters also come with the slant 6? I thought the whole point of the aluminum body transmissions were efforts to make the cars more economical once the gas crisis hit in the 70's. I really just want to get rid of the column shift. Maybe I should just scrap it and go with a Toyota 5 speed gearbox....I hear the Aussies have an adapter for that.
The od box is a great solution for fuel economy. But there are two minimum requirements; 1) enough engine to pull it,in your chassis, and 2) a matching rear gear to make it happen. The engine needs a lotta torque at a very low rpm to make this work.
The 225 is a much better candidate for success.And the low-mileage one,even better.A lot will depend on the rear gearing.And on your chassis;the heavier it is and the more wind it pushes, the less is the chance of success.
You have three things going for you;1) the bigger 225, and 2) the lightweight early-A, and 3) a small frontal area to cut through the wind. I think it will work. Perhaps a minor rear gear change to fine tune it,time will tell.

A 5-speed is a much better solution for these small engines.Actually, for almost any /6 or SBM combo

I once ran that box several years with a GVOD behind it,and enough SBM engine to pull a 2.02 final drive. I tuned her up a bit and got 32mpgUS. The same engine with 3.55s and a regular box could do just a bit better than half that,reving at about 65=3000rpm. With the 2.02combo, the revs were about 1600=65mph
 
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The od box is a great solution for fuel economy. But there are two minimum requirements; 1) enough engine to pull it,in your chassis, and 2) a matching rear gear to make it happen. The engine needs a lotta torque at a very low rpm to make this work.
The 225 is a much better candidate for success.And the low-mileage one,even better.A lot will depend on the rear gearing.And on your chassis;the heavier it is and the more wind it pushes, the less is the chance of success.
You have three things going for you;1) the bigger 225, and 2) the lightweight early-A, and 3) a small frontal area to cut through the wind. I think it will work. Perhaps a minor rear gear change to fine tune it,time will tell.

A 5-speed is a much better solution for these small engines.Actually, for almost any /6 or SBM combo

I once ran that box several years with a GVOD behind it,and enough SBM engine to pull a 2.02 final drive. I tuned her up a bit and got 32mpgUS. The same engine with 3.55s and a regular box could do just a bit better than half that,reving at about 65=3000rpm. With the 2.02combo, the revs were about 1600=65mph
Yeah, I figured a different rear gear would help my setup. Thank you for your input I appreciate it.
 
Wow AJ, you threw a wet blanket on this one. Slim didn't say what
mill he's running. If he's got his stuff together, I say go for it.

I also have a 64 Valiant with the optional "big" 225. I just rebuilt it and got it running last fall. It's 3 on the tree with the standard 3.23 gear. I put about 400 miles on it before winter and it seems to have plenty of power. I will say the column shift sucks. Even with careful slow granny shifting it tends to jam and I have to pull over and unjam it. I'm going to give it another try because I just bought some new shifter bushings that will enable me to get a more precise adjustment.

But....I've been collecting parts for a 4 speed conversion. As luck would have it, I now have both a 65 4 speed trunnion mount trans with Hurst shifter and a mid 70's OD trans with shifter and the Bellhousings for both. I finally also obtained 2 floor humps. One is a 64-65 round hole and the other is a 66 oblong hole. The earlier one is VERY rusty but has the correct shifter hole. The 66 is much better but has incorrect hole.
My plan is to try the 65 trans first as my trunnion driveshaft is in good shape and is a direct bolt-in. The OD would require a new shaft. I'll probably try both eventually just for fun. This car will be a driver (entered in this year's Carlisle) and I'd like to get decent mileage so it'll be interesting.

If you have the 170 three-speed,then Your combo is off-the-line-peppy, cuz the starter gear is 3.22 x 3.23 =10.40. The 225 has lots of grunt with that combo to motorvate an early-A.
The 225 tranny had ratios of 2.95-1.84-1.00 IIRC. The starter gear for that tranny is thus a little lower at 9.53. The rebuilt 225 will likely be a little stronger as well, with the compression restored.
I highly recommend the 273 4-spd, as it has the 3.09 low in it.The ratios are 3.09-1.91-1.39-1.00 and the splits are waaay tighter than the A903. This gets and keeps your slanty on the pipe longer, for quicker acceleration. With the 3.09 low, and the tighter splits, you may be able to lose some rear gear.
A)Your current gears may be 2.95-1.83-1.00. With a 3.23, roadgears are 9.53-5.91-3.23.
B)
With the early-A box,and 2.94s; the roadgears would be........................9.08-5.61-4.09-2.94.
Notice that the first two gears are very similar, so you lose almost nothing. Then you get a much closer gear going into 3rd, and then you can think of 4th as an od,cruiser-gear only.That 2.94 will drop your Rs about 9%. Generally 1/2 the Rpm drop will be the economy gain; so expect about 4.5% better fuel economy. This is about 3/4 mpg better on a 16 mpg car.
C)The od box may need an increase in rear gear, for the slanty to pull it on the transfers. I would expect it to need at least 3.55s,and,with those your roadgears will be;.................10.97-5.93-3.55-2.59.
Notice now that first gear has much more torque multiplication, while 2nd is about the same, and third is still plus 10%. And the od drops your Rs 20% for a 10% mileage improvement.This is about 1.6mpgs on a 16 mpg car.
I tried to keep second the same, cuz if you load up the slanty with too much second gear, it kindof looses steam.
Notice that the B) combo gives up a little off the line,to get a short 3rd. If you need acceleration in third,this is the best way to get it. The 5.61 will get you 60mph at 4500. So third now is almost a freebie. But; notice at 32mph, your Rs in second will be about 2400, a happy place for the slanty, cuz this is about where it makes peak torque..A shift into third will drag the Rs down to 1727, a very comfortable cruise. Taking second to 45mph and dropping into third; now the Rs are again about 2400, so now 3rd is very useful.Your slanty will have an easier pull to 60 with this combo than with any other listed here. It will hit 60@3240,still pulling pretty hard. Dropping into 4th, the Rs will be 60=2328(25.5 tires). Again near peak torque. I like this combo.
The C) combo is almost too much first gear.If you shift it when you normally do, it may fall flat going into second; it is just too far away. You may have to rev the engine up 15% higher than before, going into 2nd. Then 3rd is 10% closer, and 4th is strictly for cruising. When you hit that; 65=2220 rpm.
>I hope your slanty can pull that on the transfers, cuz if it gets up on the mains, the whole idea falls apart.I think it will, cuz it is very near peak torque. At this cruising-only rpm, the slanty may be wanting 40 to 45 or more,degrees of timing. There is no way to get that except with the Vcan,which takes a working sparkport. If your engine gets on the mains,the sparkport will be dead, leaving you with just the mechanical, which will be just over half that; goodbye economy.
>This is a double whammy to fuel economy,cuz you lose the Vcan advance, and the mains will be too rich. They will be delivering enough fuel for nearly full power, cuz they are seeing low vacuum/large butterfly opening. If you reduce the mains, then you are looking for a meltdown when she really is, under full power.
You have to; stay on the transfers which you can tune, and to keep the manifold vacuum up to keep the sparkport alive.
Or go to a really small 2bbl,lol.This is why I have the SuperSix set up. It has metering rods. And a metering rod adjuster built right in.
So this is a fine line to be walking, with these small engines.

Here is an experiment for you;
Pull the carb off and have a look at the transfers.Set the fast idle cam to open the the butterflies to the top of the transfers.Figure out how to index the throttles so you can easily find this point with the carb back on. Now fabricate a two-stage throttle limiter so that you can feel this point on the gas pedal. I used a coat-hanger, bent in a big old S shape to to do the job with a light initial spring and the existing heavier main spring. Now jump in and wind her up to 60mph. Then back off to the set-point and see how many mph you are currently getting from the transfers. If it ain't more than 60mph, then it will be difficult to gain anything with gearing, and with the current carb.
While you are at it put a vacuum gauge on the spark port and bring it into the cab. Take a reading at 60mph, and note the rpm. Stop the car and put a timing lite on it. Check the timing at the rpm that made 60mph. Idle it back down. Now apply the 60mph vacuum to the Vcan and read the timing increase from idle timing. Add those two together.Whatcha got?
60mph should be 2560rpm with 25.5 tires. I would expect about 25* of timing there, and 14 to 20 in the can, so ideally a total of 45*. More would probably be better.If you don't have at least 39* now, it's only gonna get worse, with a lower highway rpm.
End test.
If your numbers are less than 39* now, then there is plenty of room for improvement in the tune,as to economy under steady-state cruising.
With your newly built 2-stage throttle device, you can find a guaranteed same throttle opening time after time. This means you now have a way to tune under steady state conditions. So attack your timing devices and your AFR, and tune for maximum mph.
>I picked a spot on the hiway that was long and flat. I picked some telephone poles as start/finish lines. I got me a stopwatch. And I timed the stretch 5 times in a row,on my way to and from work,windy days excluded. Then I made a change, and next week re-ran the test. In this way I could see improvements or not. If your fueling is at least close,start with timing first. Just crank 4* in and see what happens. If your time improves, add 3 more. If it improves again, add 3 more and so on until it slows down. Then back up 3 and prove it was best.
While your dizzy is cranked of course, you will have to be easy on the gas-pedal to avoid detonation. If you pickup too much speed, you will have to reset your 2-stage.
>Once the magic number is found, and assuming the power-timing was previously established, You will have to make the magic number appear in the Vcan system.
>After that is done, you start on the carb. And if the stopwatch shows consistent improvements, continue until it slows down.
Then revisit the timing.
>By the end of summer you will have maxed out the steady-state fuel economy.
If the car becomes hard to drive with the leaned-out transfers, then you may have to sacrifice some economy.
>If the Vcan gives you grief with detonation, you will have to figure out a way to drop it out faster without reducing its all-in.
Sometimes you have to change the mechanical curve to achieve the same end result.
>I can almost guarantee you, that dialing in your current economy, in this way, will be worth way more than the theoretical 3/4 mpg of combo-B, or the theoretical 1.5 mpg of combo-C.
Whatever you do, don't melt it down, I ain't buying you a new engine!lol
Seriously, happy motoring
 
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Wow, gotta be the longest post ever^^^^. You must be retired. I'll have to print and read it on my day off. :)

So I have a 64 Val vert, rebuilt 225 head shaved 0.08, Oregon regrind cam, pretty mild, can't remember the specs right now but I think it's about. 430 lift and maybe 252*, pocket ported, gasket matched, hogged out stock exhaust manifold and soon to have full 2.25 exhaust, stock Carter BBS. 3.23 rear with 3 speed 64 tranny. Static timing is about 8-9*.

First time I took the car out after getting it running I accidentally peeled out a couple times from traffic lights. First is pretty steep at 3.09 X 3.23. I'd like to lower the freeway revs but I haven't installed the mini tach yet. It's going to be a driver.

So AJ, my first change is going to be a 65 trunnion mount 4 speed from a 65 cuda (still 3.09 first gear and 3.23 rear) then I'd eventually like to try the 70s OD I have waiting in the wings. What do you think is the better combo for all around driveability ? I have my ideas but curious what you think.
 
Wow, gotta be the longest post ever^^^^. You must be retired. I'll have to print and read it on my day off. :)

So I have a 64 Val vert, rebuilt 225 head shaved 0.08, Oregon regrind cam, pretty mild, can't remember the specs right now but I think it's about. 430 lift and maybe 252*, pocket ported, gasket matched, hogged out stock exhaust manifold and soon to have full 2.25 exhaust, stock Carter BBS. 3.23 rear with 3 speed 64 tranny. Static timing is about 8-9*.

First time I took the car out after getting it running I accidentally peeled out a couple times from traffic lights. First is pretty steep at 3.09 X 3.23. I'd like to lower the freeway revs but I haven't installed the mini tach yet. It's going to be a driver.

So AJ, my first change is going to be a 65 trunnion mount 4 speed from a 65 cuda (still 3.09 first gear and 3.23 rear) then I'd eventually like to try the 70s OD I have waiting in the wings. What do you think is the better combo for all around driveability ? I have my ideas but curious what you think.

No question about it; the deep-low and 3.23s,65=2880; so taller tires would be better.
Or else the same deep-low trans and 2.94s, with those tiny 13" tires. Those 195/75-13s are about 24.5 tall. They will get you 65=2622rpm, and the starter gear will be 3.09x2.94= 9.08, just barely enough if you rev it up a bit. 35mph will be about 2700 in second; a happy place for the slanty to be with that cam.
Nothing wrong with using the 3.23s for city fun,and if you don't mind slowing down on the hiway,60=2660. I could dig that!

The slanty will love the shorter splits of the 3.09low/direct 4th box. In comparison,the od box will be pitifully slow with a 252* cam and 3.23s.Dreadfully slow.You basically lose 3rd gear to gain the od, an unfair trade in my book, for a little engine. Sell that box now! So you never have the opportunity to try it. The rpm in od with 3.23s will be 65=2100. Good luck pulling that with a 252* cam. Well now, hold on. This is a lightweight early A, right? Yeah ok your slanty might pull that. But I doubt it will get any better gas mileage,lol.
Here is an experiment for you;
After you get your engine all tuned up, do this. Rev it up in neutral until the vacuum no longer rises. This should be your minimum hiway cruise rpm.The minimum. At this rpm your cam and head are finally working together. Reversion has stopped. The header is pulling like it's supposed to. Now you can lean out the carb, and get the timing maxed out. And just maybe that slanty will pull that 65=2100.
>But if your vacuum peak does not arrive until later,long after 2100, then you will be trying to tune while the intake is still all mixed up. You will spend dozens of hours trying different things, and in the end, you will have to drive faster to reach the efficiency that will max out the economy.
Your dad probably told you about his 49 Merc that got best gas mileage at 85 mph. You ever hear a story like that? What do you imagine could bring such a thing about? It's called efficiency. To maximize economy requires maximum engine efficiency at minimum rpm. Both together. At 2100 in od,you got that one pretty close.How about that vacuum-peak?I guess we'll see.
It is better to sacrifice a little rpm to favor efficiency, than the other way 'round.
>You can sometimes shift the vacuum-peak rpm with timing.Once you find that rpm, put the fast idle on so it stays at that rpm. Then reach down and start advancing the timing until the rpm reaches a peak.Kick off the fast idle. Now go find the new vacuum peak, and set the fast idle to that. Again move the dizzy around to maximize the rpm. When you have thus found it, put a timing lite on it and see what the engine wants,at that final rpm.Bring her back to idle and put the timing back to where you first started the test. Let her idle a while to cool off. Then rev her back up to that earlier determined final rpm, and read the timing.
Then go and figure out how to give her what she wants, yet not that she hammers herself to death with detonation.

Upon re-reading this post, it seems to me that it sounds somewhat condescending.That is not my intent.I just don't know how to write it much different without it losing it's message.
So, all the best to you and that 3.09-Direct box,lol.

and yes, semi-retired, working just 24 hours per week, just like my wife.
 
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