Well , What I know is this; in my limited experience;
for the short-tail A-body transmissions;
The 1x23 boxes mostly use the 307 front bearings, and so, they get the 4.35 retainers.
But the BBs got the 4.80 retainers, and I assume, 308 bearings, but I don't know that.
AFAIK,
>all small block overdrives came with 308 bearings and 5.125 retainers.
>The few slanty ODs that I have seen, also had the 308/5.125 retainers. I highly recommend to stay away from these, as they have the small spline output shafts and the weak od gears, that explode whenever they feel like it.
>Yes, 5.125 retainers can be lathed down to 4.80, or replaced with 4.80s.
and yes, they say, 4.35 retainers can be swapped out for 4.80s, IDK if that's true.
>But here's where it gets tricky;
There is no small-block overdrive-Bell made that doesn't have a 5.125 hole; which means, that if you want to marry a Small-block car overdrive Bell to a 307 bearinged case, yur gonna need custom parts. Or,
Or, yur gunna have to install your A833 guts, into the Overdrive case, and end up with a pile of parts that quite possibly cannot be assembled, if the cluster interferes. and still, you'll need a new front bearing to replace the one that is humming.
On another note;
>NOT all the overdrive forks I have seen, will fit on the regular A833 fork-pivots. and not all overdrive bells can be used on an SBM in an A-body, without Z-bar headaches, cuz the inboard ball-stud sometimes goes in a different place.
>The short-tail Overdrive output shafts come in two flavors, the smaller A904 size, and the bigger A727 size. So, if you currently have the small spline, sorry but I've never seen a regular A833 with a small-spline ouput, in which case, budget for a driveshaft.
>If I had a humming Overdrive, I would just recondition it.
>By the same token, I wouldn't run more than 3.55s with an overdrive........ unless I really needed Second gear to be funner. Over the decades that I have been running A833s, I find a Second Road Gear ratio of 6.82 to be big fun. Road gear is what I call the rear gear ratio, times the second gear ratio. To get 6.82, I use 1.92 x 3.55=6.82.
If you want that with an overdrive 1.67 ratio Second, you'll need 4.10s. But obviously the resulting 4.10 x 3.09= 12.67 Low-gear, is pretty doggone deep for the street. But, it makes a pretty good parade gear. In the Four years that I ran that od-Box, I never learned to like it either, and I tried and tried. At that time I had in stock every rear end, from 2.76 to 4.30, assembled with posi's, except I never had a 3.73; and I had bigger stuff too.
I even tried a different cam, different intakes, and different carbs. I really tried.
I even got me a GVod and ran it as as a splitter, for Seven nicely spaced close-ratio gears! But after a few years, that got old.
So, I know what you' re going thru. As for that box, if you have anything more than a slanty or a lo-po 318, it seems that, you either love it or you hate it, or you just put up with it.
And yes, Since I installed a Commando and GVod, I've got several spare transmissions in stock now, including a complete regular A833 with a matching BH/fork, and a your choice of shifters, both reconditioned; the one is a Hurst, and the other is a Mr. Gasket in-line shifter.
In any case, what you want to do, has been done many times. But I highly recommend that you just bite the bullet and buy the factory set-up, which will have the 727-sized output shaft, cuz AFAIK, that's the only way it comes.. and the Z-bar bracket will be in the right place.
