2.66 low gear vs close ratio

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Agreed!

I've got a hot 360 that I'm putting together for it, and I intend on putting a regular non-OD 4spd behind it. The slant is getting killer mileage, but I only drive about 10 miles a day reaching speeds no greater than 50mph. Even if I only get 10mpg with the 360, it'll only cost me $2.50 to get to work and home a day!

Besides, if I wanna cruise slow I'll drive my '51 Business Coupe...
 
Here is a simple nut shell;

Wide ratio is a good street driver. Best over all for stock to an aggressive machine.
The close ratio is fine as well. Best if used in a serioous street machine or drag car. If it is use on a racing application, drag or road, then the close ratios lend well for keeping the engine/car in the perspective power band being used.
In a drag car or serious street performer, a set of 4.10's and closer ratio's allow fo the quick get up and go off the line into the power band where it can stay for the duration and change to the next gear to stay in the power band (lower half) where you would likely want it most.

The O.D. Best used for a truck, low gear ratio and Hwy. cruiser. It can be used with a low gear set (Like 3.23's and down) since it has the deep 3.09 first. So something like 3.55 and lower gears can actually feel a good bit better than the 2.66 ratio of the other trans. Ending in a .69 creates a heck of a tall gear for driving.

If you have time to sit down and calulate every ratio with your gear ratio and spread it out so you can see how every gear works with your gear ratio, then you can go further with tire sizes and RPM's of the engine.

It is a lot of work, but a greter knowledge and uderstanding you will have for a better choice for YOUR car and needs. A/J did a tone of writing. (My eyes hurt!) and the graph the followed helps a lot.
 
rmchrgr

Gears is gears.
If you are starting in 2nd now,the o/d box will be very nearly exactly the same pos. The idea of putting more gear in the back will help with first gear for sure. But absolutely nothing will help the splits. And if you try to put any torque into the O/D 4th, with that 400, it will rip all the teeth off that gear.On their way to the bottom of the case, there's no predicting what other damage those pieces will do.

I've shredded two of those; one with my 360, and one with my 4bbl teener winter motor. It's very easy to forget about that poor gear when banging through.One was a .71ratio and the other was a .73ratio. Buying swap meet trannys, I always kept one for a spare on the premise that I would someday again forget.

I did buy a GearVendor unit and hung it back there. I used it for a gear splitter. That was pretty cool at the dragstrip.........
the A833ratios are ..................3.09-1.67-1.00-.73, and splits are 54%-60%-73%
With the GV............3.09-2.41-1.67-1.30-1.00-.78-.57 splits are .78-.69-.78-.77-.78-.73

With a .57double O/D you can run any rear you want. So I chose a 4.88 for the 1/8th mile.This put me at 93mph at 7100 in second over. Catch that! Just one stick shift, and two electric,faster than fast, shifts. With tirespin, the tach more or less got "stuck" at 7000 for pretty much all of the run. On the way home 4.88 x .57 = 2.78 cruise gear was good for 2250 at 65mph..
'Course around town, 4.88 x 3.09 = 15.08 is the absolute worst first gear you could imagine.(Well except for 6.68 x 3.23 =21.58 ). And second 4.88 x 1.67 = 8.15 is almost as sucky,(as goldduster with an 8.59starter is contending with). I ran 4.3s for a while that summer, cuz I thought I would 1320 it. But it soon became apparent that 93 in the eighth was plenty fast enough for me. So since I now knew what starter ratios sucked (the 15.08 and,4.30 x 3.09 =13.29, and the aforementioned 8.15), I went for something in between; say 11/1. That meant 3.55s. These give a very nice 10.97 starter gear. And a fabulous 2.02 cruiser gear, giving 1631@65mph.
There was a problem tho. I got real tired of gear-splitting around town, but I was married to it. The engine was very unhappy pulling those huge splits without the splitter. About that time my little 223* cam dropped 2 lobes, and in my infinite wisdom I replaced it with a 230*cam, which really didn't like the 2.02 O/D, nor the factory splits.
So I went into research mode. I knew I wanted to keep the 11/1 starter gear, and by a little testing I determined that my new cam was happy at about 2200@65. So it just so happened,I discovered, that Mopar, back in the early 60s made a 3.09low gear in the standard 2.66 flavor.
My new ratios were 3.09-1.92-1.40-1.0-.78GV.the splits are .62-.73-.71-.78 Good enough I thought, I have a 5spd. Perfect actually; I got to keep the 11/1 starter. I got 2236 at 65mph for cruising. AND I can still split gears when it's hammer time. Splitting the first two gears,the split ratios are 3.09-2.41-1.92-1.50, and splits .78-.80-.78 this gets me 109@7200 in second-over. That's just about 1500 rpm drops between gears! You cannot imagine my glee. In practice, I might shift at 6500, so the drops would be 1365. I say would cuz on the street, even with 295s. the tach just pegs at redline 'til about 80mph, as it spins it's way to the top, killing the clutch damper springs, and melting the tires..
I cannot relate to you how addictive this is.The sound coming out those dual 3 inch turn downs, when the engine is screaming 6800 for 5 or 6 seconds is ..................no words .And the pow,pow,pow of the shifts.....no words.And the insane laughter from my lips, and the screaming/crying passenger.....no words
Sorry OP I got sidetracked again...........

You will have to pry this combo out of my cold dead fingers!
 
AJ/FormS said:
absolutely nothing will help the splits.!
Click to expand...

This is a true but you can lessen some of the ill effects by matching things accordingly, especially when it comes to torque and where it does the most good for a a given combo.

If you go on the GV site and select NP435, the first thing they say in their blurb is that adding a GV unit to an NP435 is about the best thing you can do, they were practically made for it.

If only there was a shorter shifter for it.

I had an NP445 in my old W100, that trans was night and day better than the 435 - usable first, better splits, just an all-around better driving trans.
 
There is no matching for you. You already have 400cubes, and a reasonably lightweight pick-up.You already know the splits suck. The splits will suck no matter what rear gears you put back there and no matter what tune you put into that 400. And to sink a ton of cash into a GV to be used as a splitter,is, as I have detailed,mostly a PITA.
And the O/D 833 will be very nearly the same.
My friend, you need a pass-car non-o/d 4 speed or an automajic.
I have an 84 D100 with a 4bbl-teener, and a 2200stall 904 and 3.55s,and a traction aider, makes it a pleasure to "flick" around. Well "flick" is stretching it, but she slides pretty good with 275/50s. With that really long wheelbase it's really easy to control.

IMHO a 727 with a stockish TC and 3.55s would be a real pleasure. For $500 to $700 you could be giggling like a little girl in Daddy's arms. I'd even try it with 3.23s.
Sure would beat the hate you're feeling now....
 
vntned
That tranny is perfect for 3.91s and your 170.All except those pesky splits.Unless you supercharge it!
This gearset really wants a car-weight to engine-size ratio of not much more than 11/1, and an engine with plenty of torque that can pull from idle to 2500 or a bit more.It's pretty much essential that the engine be able to pull hard from just off idle; say 1200rpm.
At 170 cubes, you are on the short side all right.I'll assume your vehicle is an early A with a weight of 2600pounds. Then 2600/170 = 15.3/1. That's pretty out there. If you are heavier it get's worse. You probably won't be much lighter. Not so it counts anyways. If you did turbo-charge it, you might/could get into the zone.Lotsa cash tho. Good used 225/318 would be way cheaper.
 
My OD is noisy anyways, it's going away. And I've already got the 360 mostly finished. It'll be cheaper to swap it than boost it.

Not to mention, that I'm really craving a hooligan! A car to scare myself with.

And yes, my car is fairly light. It's a no option, 2dr sedan, '64 Dart.
 
Can't go wrong with the 2.66
However, the 3.09/direct box will let you run one or two rear gears smaller, if you are thinking of any roadtripping.And a stout street360 will hardly feel the 1-2 difference, AND 3.23s with 27 inch tires makes second gear at 2700rpm equals 35mph, the perfect rpm to hammer it.3.55s would up it to3000, and that is not a good cruising rpm.Cruising at 3000 tells the world you are looking for trouble. 2700 says your ready,willing and able, but not actively seeking.Just a little clutch and blast off.
Stout means a short period cam with plenty of compression, to make big low-speed torque.But again, if you intend to go racing,and have a big cam, and are gonna run 4.30s, then it really doesn't matter.
I run 3.55s with the 3.09low, only because I have the GV for an overdrive.For me the minimum cruise rpm is around 2200, where my engine vacuum peaks. So 3.55s is about the minimum gear for making good fuel mileage. If I had less cam, or did not have the GV, I would be running 3.23s. Already tried 'em. Loved 'em. But 3.23s would drop my cruise rpm to 2000@64, which puts my cam back into some degree of reversion, and negatively affects my fuel mileage.

So then the big question to answer, to help decide 3.09/2.66 low is;(actually there are 2 questions),Do you already have a trans and what is your intended usage?
If you already have the 2.66, you ae golden, just go with it.
If you have already purchased a rear gear,just go with it.
If you are a streeter with a 225* or smaller cam, and want to put some highway miles on, then the 3.09low with 3.23s can be a really nice choice.
A little bigger cam will like 3.55s and the 3.09
A little smaller cam will pull 3.55s with the 2.66, or 3.23s with the 3.09; but will likely favor the 3.55s, especially in the higher gears;mostly 4th.
If you are going racing, or for most other applications;it doesn't really matter. If your car really hooks, the 3.09 might get you out of the gate a little quicker.

If you are a streeter I think it would be more important to think about second gear and what speed you will be tooling around at,and get the rear gear that puts your engine in the happy zone, and forget about first for a bit. And that takes us back to paragraph one.
 
AJ, you can stop typing now because the Passon 18 spline OD is the answer! 2.66:1, 1.59:1, 1.00:1, .80:1 OD. 18 spline! Fits in a regular case!

Comes in 'kit' form for just under $2k or as a built unit for just under $3,200. Pricey? Yes. Solves problems with crummy factory design? Worth every penny. Slap it into your existing case and be done with bad gear spreads while keeping overdrive.

There's also his 5 speed deal but that's *ahem* a little more coin. He's also not at full production yet so people on the list are still waiting for units. The 5 speed is probably not for me but I'm thinking hard about the kit, just might be my ticket.
 
I would disagree with "crummy factory design"
I think them very well designed - for their intended application.
 
He is talking about the placement of the factory overdrive gear vs. where Passon places it.
Yes! Crummy factory placement.

I didn't know you could purchase it in kit form. Hummmmm
 
Unfortunately a $3200 trans is out of my budget...

As far as my build goes, it's basically a copy of a recipe on moparts and done by Mopar Muscle Magazine. 360, 0.060" over, speed pro H116CP Pistons, measured scr of 9.8:1, professionally ported 974 heads, 2.02s and 1.60s, Comp Magnum 230@50 duration, .480" lift 110lsa, and either a LD340 or PerformerRPM intake. Other wise stock parts.

And I've already got the rear 3.55 gear with a Sure Grip, so I'm gonna stick with that. It MIGHT make it to the track one day, but it's not intended as a drag racer. More of a backroads brawler.
 
rmchrgr said:
AJ, you can stop typing now because the Passon 18 spline OD is the answer! 2.66:1, 1.59:1, 1.00:1, .80:1 OD. 18 spline! Fits in a regular case!

Comes in 'kit' form for just under $2k or as a built unit for just under $3,200. Pricey? Yes. Solves problems with crummy factory design? Worth every penny. Slap it into your existing case and be done with bad gear spreads while keeping overdrive.

There's also his 5 speed deal but that's *ahem* a little more coin. He's also not at full production yet so people on the list are still waiting for units. The 5 speed is probably not for me but I'm thinking hard about the kit, just might be my ticket.
Click to expand...

and the splits are 60%-63%-80%
I am delighted to see an alternative selection, but I don't see this as a solution to everybody's problem. If you build your engine to work with these ratios, it can be a good alternative.
These ratios would work with an engine that likes to be shifted between 5000 and 6000, thus having a powerband requirement of 2000 to 2400 rpm. That's doable. Say a stout teener or a stockish 360, or any engine tuned to favor torque in the lower Rs
But if your engine wants to be shifted at 7000,thus professing a power peak around 6000, the Rs will drop(2nd) to4410; and the powerband requirement will be 7000 - 4410 = 2590. That's a bit of a stretch, cuz it's a long haul to where the power is. But the next gear is way too close and if it can take full power/torque (I don't know that it can), then you can outshift 3rd at around 6700, to drop in at 5360( to center the run on the powerpeak) That might trap ok. But it has to to, make up for the big early splits.
So in my mind these ratios are more suited to a DD, and are only a little better than the Chrysler O/D box (with %splits of 54-60-73). But if the od gear can take the heat then that would be a big bonus. Especially for guys like me that might forget what box they're shifting this week!


As for me I would prefer what I already have.
 
vntd
Your engine is a lot like mine.And I also run 3.55s. If you don't already have a tranny, then I very highly recommend the 3.09low/Direct 4th box. And I also urge you not to use the OD box.
I've tried em all with my 230* equipped 367 cuber. The power band of that 230/110 is as broad and flat as Texas?, So it does well with the ratios in the standard 2.66box. The 3.09 just gives it a real kick off the line. And you don't need to slip it out. Once you get the tune into it,it will be;just blip the throttle and dump it.
The 3.09 takes off with 3.55s, like the 2.66 takes off with 4.10s.And it allows a short shift into 2nd. Or not.
 
AJ/FormS said:
and the splits are 60%-63%-80%
I am delighted to see an alternative selection, but I don't see this as a solution to everybody's problem. If you build your engine to work with these ratios, it can be a good alternative.
These ratios would work with an engine that likes to be shifted between 5000 and 6000, thus having a powerband requirement of 2000 to 2400 rpm. That's doable. Say a stout teener or a stockish 360, or any engine tuned to favor torque in the lower Rs
But if your engine wants to be shifted at 7000,thus professing a power peak around 6000, the Rs will drop(2nd) to4410; and the powerband requirement will be 7000 - 4410 = 2590. That's a bit of a stretch, cuz it's a long haul to where the power is. But the next gear is way too close and if it can take full power/torque (I don't know that it can), then you can outshift 3rd at around 6700, to drop in at 5360( to center the run on the powerpeak) That might trap ok. But it has to to, make up for the big early splits.
So in my mind these ratios are more suited to a DD, and are only a little better than the Chrysler O/D box (with %splits of 54-60-73). But if the od gear can take the heat then that would be a big bonus. Especially for guys like me that might forget what box they're shifting this week!


As for me I would prefer what I already have.
Click to expand...

I think the Passon gears are rated to like 750hp or something. How high were the original 18 spline boxes rated to? If you're really pounding on a four speed in a race application, you're probably stepping up to a Jerico or Liberty anyway so all the arguments about how strong these things are seem moot too me. There are people that have raced those units though and they seem to hold up well, you don't read about guys breaking them.

For my truck application, it would be a great solution and cheaper than a GV. I'm not power shifting or drag racing. Most of the time my rpms barely crack 4,000 let alone 7,000. I imagine the trans would last as long as I am able to drive the thing. Plus, it will bolt right in with no mods except for cutting a hole in the floor to put the shifter in the right spot.

If I ever want to see any sort of mileage, I have to change the current 484/284 cam to something smaller which should also help torque across the board. Maybe some more rear gear too, like a 3.55 or a 3.73 if I can find one. I think it will be a great combo if I am able to work it out.

I'd be thrilled if I could knock down 16 mpg which is what my old Cherokee sport used to get.
 
AJ/FormS said:
vntd
Your engine is a lot like mine.And I also run 3.55s. If you don't already have a tranny, then I very highly recommend the 3.09low/Direct 4th box. And I also urge you not to use the OD box.
I've tried em all with my 230* equipped 367 cuber. The power band of that 230/110 is as broad and flat as Texas?, So it does well with the ratios in the standard 2.66box. The 3.09 just gives it a real kick off the line. And you don't need to slip it out. Once you get the tune into it,it will be;just blip the throttle and dump it.
The 3.09 takes off with 3.55s, like the 2.66 takes off with 4.10s.And it allows a short shift into 2nd. Or not.
Click to expand...
I'll add a comment: vntd is in central NC in the low foothills; a 3.09 won't get as much use unless he is driving in town a lot. A 2.66 will be a lot more useful roaring around the southern Appalachians; finding the right gear in sharp hairpins turns requires a useful 1st from time to time, and the 3.09 is not it. So, vnted, I would look at your intended driving terrain; if in Greensboro a lot in stop and go traffic, or never in the Blue Ridge, then 3.09. If not, and you go roaring around up towards Patrick and west of Wilkesboro up into the Blue Ridge, then 2.66 fer sure.

The OD box is just a 3 speed and having raced one for while (actually a 4 speed with too high a rear gear, which made 4th about useless), they really are limiting. You'll always find some corners needing a gear and RPM combo that you don't have with 3 gears. Same for the Passon 4 speed OD mentioned. The OD is for interstate cruising and is nice there, but is a real compromise in hard driving.
 
I've been following this thread because I've wondered what gear set I had in my transmission, and I had a couple of questions.

- If the trans is already in the car and driving, is there away to find out what gear ratios you have without pulling it out and opening it up?

- Were there any A-body trans built '70 and later (newer) that had the 2.47 gear set? From the factory, what would have the intended of a vehicle that had a 2.47 gear set?

I'm barely getting my Duster together but been driving it on the weekends. I haven't opened up the diff to verify my rear gear, but the tag says 3.21:1.

So far, the transmission seems to shift good and the RPM's are right (i.e. pulls good in the appropriate gear even at a slow cruise). 1st gear isn't very short at all, and neither is 2nd gear.

I guess that's why I wonder what I have in there. I did have the transmission rebuilt, but forgot to ask what ratios I had. The car previously had a 3 speed (A230).
 
I have been following this thread as well. I'm in the planning stages of building my 82 D150 2Wd shortbed into a street bruiser. It's currently a /6 833 OD. I Have been looking at the passion 18 spline drop in kit because I'm going to be building a 400 based stroker so need something to support the power but would really like to keep OD on this build.

But now AJ has got me thinking a regular 833 and gear vendor might be my ticket.
 
Hmmmm, I do like the idea of a longer 1st gear...

And I come from having a lot of Mopar pocket rockets. Omni GLHs, Shelby Daytonas, Shelby CSXs and Neon R/Ts. None of these were straight line only cars. They were more focused on flying through the curvy backroads than straight lines. Full suspension mods, sticky tires, close ratio transmissions, etc.. I want to do the same type of driving in my dart.

I've already got the full suspension and brakes done with all the parts from PST and Hellwig I could afford. And added wide wheels an rubber on all corners. It handles like it's a modern car. It's also got a set of Recaros up front to keep me in the seat around corners. A quick ratio steering box is next on the list.
 
rmchrgr said:
I think the Passon gears are rated to like 750hp or something. How high were the original 18 spline boxes rated to? If you're really pounding on a four speed in a race application, you're probably stepping up to a Jerico or Liberty anyway so all the arguments about how strong these things are seem moot too me. There are people that have raced those units though and they seem to hold up well, you don't read about guys breaking them.

For my truck application, it would be a great solution and cheaper than a GV. I'm not power shifting or drag racing. Most of the time my rpms barely crack 4,000 let alone 7,000. I imagine the trans would last as long as I am able to drive the thing. Plus, it will bolt right in with no mods except for cutting a hole in the floor to put the shifter in the right spot.

If I ever want to see any sort of mileage, I have to change the current 484/284 cam to something smaller which should also help torque across the board. Maybe some more rear gear too, like a 3.55 or a 3.73 if I can find one. I think it will be a great combo if I am able to work it out.

I'd be thrilled if I could knock down 16 mpg which is what my old Cherokee sport used to get.
Click to expand...

Either you didn't read my earlier posts, about wide ratio boxes, and low rpm/hi torque engines, or you didn't understand it.
You have a 400 with a 284/484 cam. That can be a powerful engine, when it gets wound up. But doesn't take much of a mis-tune to make it mushy down low, early in the rev range.A well tuned fresh360-2bbl, can outpull a poorly tuned 400,possibly,like yours, to 3000 or maybe even,4000 rpm.
So,if you are operating your high-rpm engine in the 2000 to 4000 window,It is no wonder you are disappointed. And I will almost guarantee you that the Passon box will be no better than the A833 o/d, which is as good as the same as your NP. The splits are only a few % apart. Again, the 3.55s will help get it off the line, but after that,the splits will drag it down same as before, just a few mphs sooner. There is no getting around that. I've tried several different chunks with the od box, and the results were always the same.The splits are just too far apart with any cam just slightly larger than stock.
Like I said, you need a standard 4 speed with about 72% splits, or an auto.
Or like you said, drop that cam, like a hot potato.Put something in there that pulls right off idle, and take the granny outta the tranny, or swap it to the 833 od that you already own.
Since that's the most bang for the buck, that's what I would do; stock type short-period cam, and the 833od, a sharp tune,and 3.23s to 3.73s.
You will be smiling
 
vntned said:
Hmmmm, I do like the idea of a longer 1st gear...

And I come from having a lot of Mopar pocket rockets. Omni GLHs, Shelby Daytonas, Shelby CSXs and Neon R/Ts. None of these were straight line only cars. They were more focused on flying through the curvy backroads than straight lines. Full suspension mods, sticky tires, close ratio transmissions, etc.. I want to do the same type of driving in my dart.

I've already got the full suspension and brakes done with all the parts from PST and Hellwig I could afford. And added wide wheels an rubber on all corners. It handles like it's a modern car. It's also got a set of Recaros up front to keep me in the seat around corners. A quick ratio steering box is next on the list.
Click to expand...
That is a cool collection of older Mopar pocket rockets! LOL My own thinking about an A body for rallying does not even consider a 3.09 1st ...it is between the 2.66 and the 2.47 1st gear. My planning for an Opel Manta for rally using a 5 speed T-5 was to start with a 2.22 1st....
 
nm9stheham said:
I'll add a comment: vntd is in central NC in the low foothills; a 3.09 won't get as much use unless he is driving in town a lot. A 2.66 will be a lot more useful roaring around the southern Appalachians; finding the right gear in sharp hairpins turns requires a useful 1st from time to time, and the 3.09 is not it. So, vnted, I would look at your intended driving terrain; if in Greensboro a lot in stop and go traffic, or never in the Blue Ridge, then 3.09. If not, and you go roaring around up towards Patrick and west of Wilkesboro up into the Blue Ridge, then 2.66 fer sure.

The OD box is just a 3 speed and having raced one for while (actually a 4 speed with too high a rear gear, which made 4th about useless), they really are limiting. You'll always find some corners needing a gear and RPM combo that you don't have with 3 gears. Same for the Passon 4 speed OD mentioned. The OD is for interstate cruising and is nice there, but is a real compromise in hard driving.
Click to expand...

This is correct, I missed the location information.

You can almost never have too many ratios. With the OD box and the GV, there are seven usable ratios; 3.09-2.41-1.67-1.30-1.0-.78-.57. Unfortunately you cannot downshift into any GV ratio. Or more correctly, during the downshift you cannot be putting power through the box. So that won't work for roadwork. Which is why, after a rebuild, I don't use it any more.
It's hard to beat a regular 5 speed. Or even a 6 with an SBM.
 
JoesEdge said:
I've been following this thread because I've wondered what gear set I had in my transmission, and I had a couple of questions.

- If the trans is already in the car and driving, is there away to find out what gear ratios you have without pulling it out and opening it up?Yes

- Were there any A-body trans built '70 and later (newer) that had the 2.47 gear set? From the factory, what would have the intended of a vehicle that had a 2.47 gear set? AAR ROAD racing

I'm barely getting my Duster together but been driving it on the weekends. I haven't opened up the diff to verify my rear gear, but the tag says 3.21:1. Is there a question here?


So far, the transmission seems to shift good and the RPM's are right (i.e. pulls good in the appropriate gear even at a slow cruise). 1st gear isn't very short at all, and neither is 2nd gear. guess that's why I wonder what I have in there. I did have the transmission rebuilt, but forgot to ask what ratios I had. The car previously had a 3 speed (A230).
Click to expand...

As to figuring the tranny ratios; Drive the car in 2nd gear up to exactly 40mph. Note the exact rpm. Shift into third and drive it back to 40 mph, and now note the new rpm.Stop the car. Take the smaller rpm and divide it by the larger. This will give you the 2-3 %split. Compare to the posts. .
Example: 40mph 2nd = 3063 rpm, and 40 in 3rd = 2233 Then 2233/3063 = 72.9%split. This would be a 2.66 box. The 2.47 box would be 75.7%. the od box would be 59.9%. The rpms will be different depending on the rear gears and which trans is involved. I just threw these rpms out there as an example. The % splits is what tells the story.
The AAR was a short lived series, maybe a couple of years, IDK
There are threads on how to figure out your rear gear.
Thx for dropping in.
 
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