4 Speed Conversion

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DadsNewToy

DadsNewToy

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I live in Ontario Canada. I have a 1970 340 Automatic Duster with console. But I long for a 4 speed. Does anyone have a guesstimation of what it would cost to convert an automatic to a 4 speed. What kind of shop would be able to do this? I have the tranny, petals and drive shaft from a 1973 340 Duster I used to own. Rest her soul.
 
Each time I've done it , I always swear it will be the last !! Lol !! ( four times including a 4x4 truck ). But they are so fun to drive!!!
 
Love 4 speeds but the old shoulder doesn't like it at all any more.
 
DadsNewToy said:
I live in Ontario Canada. I have a 1970 340 Automatic Duster with console. But I long for a 4 speed. Does anyone have a guesstimation of what it would cost to convert an automatic to a 4 speed. What kind of shop would be able to do this? I have the tranny, petals and drive shaft from a 1973 340 Duster I used to own. Rest her soul.
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I think you're going to pay a whole crap load to have someone else do it and do it right and "care" that they did it right! This is the kind of crap that I tell people to do themselves because when inevitably it doesn't work they won't even know how to fix it. And then they have to keep taking it back till someone gets it right. When it's all really literally a complete bolt in kind of deal. Withstanding cutting that hole in the floor board. But the dog house is a perfect template to do it with. I can't remember if you said there you want to keep your console or something? I would suspect over twice what you paid for the 4 speed and all the stuff to put it in. If you want it done right with warranties and stuff like that.
 
DadsNewToy said:
I live in Ontario Canada. I have a 1970 340 Automatic Duster with console. But I long for a 4 speed. Does anyone have a guesstimation of what it would cost to convert an automatic to a 4 speed. What kind of shop would be able to do this? I have the tranny, petals and drive shaft from a 1973 340 Duster I used to own. Rest her soul.
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Plan on about $4500 - $5000 for all new parts. If you have the transmission, that will save you about $1400. If you have the pedal assembly, that will save you another $300. I can't say for sure if the auto trans console will work for a 4speed. I would guess, at the very least, you'd have to get a new top plate to accept the 4 spd shifter.

I just did this on my '69 Charger, and will attach the list of parts I needed for mine. I've heard of others finding all the parts used for about $2500-$3000, but it took them a while to round them all up. I have gotten quotes from Brewer's Performance and Passon for all my parts. I went with Brewer's because they were a little cheaper, and were within driving range to pick it all up to save the shipping freight.

Your A-Body will need some different parts than my B-Body ( i.e.... I know the torque shafts mount differently), but overall it should be pretty close. Here is a parts list I copied from my quote from when I just did my Charger.

Brewers 1.JPG


Brewers 2.JPG


Brewers 3.JPG


Brewers 4.JPG
 
Streetsboro Rick said:
Number one question does the motor have a pilot bushing!?
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No automatic car has a pilot bushing. It has a spot to accept one, hopefully. If the crank doesn't have the right depth to accept the 4-speed input shaft, I've heard of people nipping a little bit off of it to make it work,
 
Frnknsteen said:
Plan on about $4500 - $5000 for all new parts. If you have the transmission, that will save you about $1400. If you have the pedal assembly, that will save you another $300. I can't say for sure if the auto trans console will work for a 4speed. I would guess, at the very least, you'd have to get a new top plate to accept the 4 spd shifter.

I just did this on my '69 Charger, and will attach the list of parts I needed for mine. I've heard of others finding all the parts used for about $2500-$3000, but it took them a while to round them all up. I have gotten quotes from Brewer's Performance and Passon for all my parts. I went with Brewer's because they were a little cheaper, and were within driving range to pick it all up to save the shipping freight.

Your A-Body will need some different parts than my B-Body ( i.e.... I know the torque shafts mount differently), but overall it should be pretty close. Here is a parts list I copied from my quote from when I just did my Charger.

View attachment 1715175649

View attachment 1715175650

View attachment 1715175651

View attachment 1715175652
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Of course they B/E transmission would have a different tail shaft also. Then yes collecting Parts is a good way to go also if you have a little time and patience. I bought my four speed for $800 that included the shifter, linkage, and the bellhousing. Of course I had to pay $75 for the floor hump and 200 for the paddles and I had to buy a couple of pieces from Brewers to make it all work correctly. But in the end as far as a parts collection I don't think I had $1,500 into it all. Now as far as reliability compared to a new one I've been drag racing this in an 11-second car for 3 or 4 years right up to last weekend and still working just great. Truly and honestly I think buying new is hasty. Collecting the parts up usually doesn't take long because they're out there and decent deals are also out there. And these things are extremely cheap and easy to rebuild.
 
Just my two cents- yes this can be an expensive proposition. If you are going stock, the console itself and the top plate are unique to 4-sp. Swing pedals come in lite duty and heavy duty, the HD has bearings not bushings. I agree that the most expensive part is going to be your crankshaft, if it is able to accept a pilot bushing. I would check all these things first before investing anymore money in the project. Coffee is still here for jpar.
 
I didn't want to discourage anyone from trying- but no, I haven't seen any cranks that will accept this swap. I have always had to build the motor with a "stick" crank and then install.
 
j par said:
If the crank doesn't have the right depth to accept the 4-speed input shaft, I've heard of people nipping a little bit off of it to make it work,
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Yep,... the previous owner did it on my Barracuda. It's a 400 with a cast crank. There is a roller bearing that presses into the opening in the back of the crank where the nose of the torque converter would normally go. Then you have to cut about 3/4" off the end of the input shaft. Not the best way, but it seems to be working fine in mine. Brewer's sells those bearings too. Pictures shown below of bearing and how it installs

PB5300-1.jpg


Installed.jpg
 
Every 340 I have had have been drilled from the factory, just add the bushing. I never had one later than 1973 so they may not be drilled but all the early ones have been in my case.
 
I believe all the 340 cranks up to 1972 were forged cranks and were drilled. What I don't know is if they were all finish drilled to accept a pilot bushing, or if they were just "Pre-drilled" with a smaller, shallower hole. I've seen forged crank big blocks that were just pre-drilled, but weren't big enough or deep enough to accept a pilot bushing.

I think they switched to cast cranks in 1973, and doubt that they were drilled for a pilot bushings. I could be wrong, but I don't remember ever seeing a cast crank drilled for a pilot bushing.
 
DadsNewToy said:
I live in Ontario Canada. I have a 1970 340 Automatic Duster with console. But I long for a 4 speed. Does anyone have a guesstimation of what it would cost to convert an automatic to a 4 speed. What kind of shop would be able to do this? I have the tranny, petals and drive shaft from a 1973 340 Duster I used to own. Rest her soul.
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You are most of the way there; In Canadian bucks, another $2500 should get it done with change back.
But you will probably want to go up one rear gear size to compensate for the lack of the TC off-the-line hit. And your SG will probably want to be tightened up.
I have done this swap a few times,Pm me if you like.
The list in post #9 is pretty extensive.
Check your lowgear ratio to see if it hopefully is a 2.66
 
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BTW
my 71 360 crank was drilled deep enough and the pilot was roughed in.
I could have used the NAPA bushing, but chose the bearing instead.
That was 1999 and well over 100,000 miles ago
 
AJ/FormS said:
BTW
my 71 360 crank was drilled deep enough and the pilot was roughed in.
I could have used the NAPA bushing, but chose the bearing instead.
That was 1999 and well over 100,000 miles ago
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My current car is a 1970 340 auto. It has a 72 date code block. I had a 1973 Duster 340 4spd until it rotted away in my driveway. Kids, mortgage, college, all that. But I gutted it before hauling away the body (RIP old friend). I have the engine, flywheel, bellhousing, clutch petals, transmission, shifter, drive shaft, etc. And the reverse light. Of course everything needs to be cleaned and the tranny rebuilt but I believe I have all the parts.
 
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