1/.75=1.33 ratio = the close ratio T/A gear set of
2.47-1.77-1.34-1.00
To use a Chevy trans behind a Mopar, you install an adapter Bellhouse, a GM clutch-disc, and matching TO bearing and fork.
But before you get too excited, you still have to deal with the GM Speed-O drive gearing. and IDK about the yoke or the shifter-pad location.
By ratio; There were four 1x23 input A833-boxes for Mopars.
3.09-1.92-1.40-1.00; the "Commando", deep-low
2.66-1.92-1.40-1.00; the "standard" from 66>69 and beyond
2.47-1.77-1.34-1.00; the "T/A close ratio", beginning in 1970
3.09-1.67-1.00-.73od; the ultra-wide ratio, "od-box"
and there was a version with a .71od box
Which ratio you choose, will depend a lot on your combination and intended usage. See Note-1
By physical dimensions, in the Mopar Camp,
there were several variations, that I know of;
3 main boxes,
3 retainer sizes, with matching BH's
2 lengths of tailhousings,
2 cover-types with different interlock systems and forks,
3 shifter pad locations,
two types of speed-o drive gear systems,
and iron or alloy constructions.
Also found are several different BellHousings, not all of which fit properly into every Mopar body.
So the selection process for installing a Mopar A833trans into a Mopar, begins with the BH that best fits the body . Then;
Any of the boxes will bolt to almost any factory bellhouse, but the retainer has to be matched to it,to best center the trans, which will then dictate which box to use.
AFAIK any tail will bolt to any box, but the shifter-pad may end up in awkward places depending on which body-style you install it into. Where the shifter-pad ends up, dictates the shifter rods to be chosen; long of short, and the reverse rod can be an adventure. The one thing that seems to never change among the Mopars, is the trans mounting location.
I know as good as nothing about the Chevy stuff, except, AFAIK the only part in that GM box that will interchange with a Mopar is the Low gear.
Note-1
As for me, I like second gear to top out around 7000@65 mph. this takes a Roadgear (trans gear times rear gear) of around 8.70
With the Commando/Standard box, this will require a rear gear of 8.70/1.92=4.56s But with
a 1.77 T/A box, needs 4.88s, and with
the 1.67 od box requires 5.28s
Thus with all of these, still in Second gear, 32.5mph will be half-rpm= 3500rpm which is a great place to to launch from, with almost any Mopar engine.
The problems start with what happens in First gear, and again with the cruising rpm.
About the lowest First gear ratio I would entertain for my hot-rod 367, is 11/1 Roadgear. None of these boxes will marry a 65=7000 in Second, with an 11/1 starter gear; so right away, I have to make a compromise. And for street use, the 11/1 starter-gear ceiling trumps, where it tops out at in Second gear. And the cruse rpm trumps them all. This makes choosing the rear gear easy, and then matching the other gears to the application, and then fine-tuning the power-delivery with engine torque.
For example;
3.23s will cruise at around 65=2600 in Direct Fourth. Thus you have Starter-gear choices of 3.23 times one of; 3.09/2.66/2.47 equals 9.98/8.59/7.98 and; Unless you got a BB engine, your only choice is likely to be the 9.98, and so your only trans choice is the 3.09 low, which comes in two flavors, namely; the Commando or the OverDrive.
Which one you chose will depend on your engines ability to pull the ultra-wide ratios in the od-box ..... or not.
But if you have a hi-torque engine then, the 8.59 Starter gear could also be on your radar. But be advised, that 1.77 Second gear, with the 3.23s, will get you 84mph@6000, which is waaaaaay up there for a streeter and you may only rarely be able to go there. Whereas 65mph in 1.77 Second is only 4630rpm, so if your looking for Rapid Transit, anything less than a BB, is not gonna be competative. But the T/A box is a great fun-choice for a stout 318 with a Short-period cam in it , and more than 3.23s out back, loke maybe 3.73s, which will get you a Starter of 3.73 x 2.47= 9.21, and 65=5340rpm which will like a cam that power-peaks around 5000/5100.
If you want more Power off-the-line, you go with a 360 engine/3.55s and a new cam that power-peaks a lil lower.
In either case, you would pump the pressure up as high as you have anti-knock gas for, to maintain the low-rpm energy.
But if you just want low-ET in the zero to 60 arena, then, that takes you back to gearing the car to run out of power just before 60 mph, in Second gear, at as high an rpm that you dare to spin, and with the supporting cam and heads ........ but be advised, you cannot harness all that power on the street anyway, so now you are building a different car.......
Just so you know, my favorite combo is the A833 Commando with 3.55s, and a cam no bigger than
[email protected] cam. To marry that, I used a 360 engine @ 11/1Scr that produced near 195psi. This produced a killer bottom end that takes off at any rpm, yet with 3.23s cruises at 2600 with 27" tires. The 360 is way more engine than the chassis can handle and I believe, a 318 would have sufficed. But you know, I had at least one example of every LA SBM ever built, so the 360 was a natural choice. I did not know that alloy heads would support 195 psi until I built one, so was not expecting as powerful a 360 as I got. Knowing this now, after the fact, a 340 would have been plenty. and a 318 would have just spun the tires not as badly as her bigger brothers.
But you know, the 360 falls together at 10.7 Dcr, cheap and easy at 335hp with the alloy heads, so it was kindof a "no-Brainer" for me. Plus with a 224 cam, it made fabulous fuel-mileage, in overdrive.
