The Dodge Challenger Message Board

I know that the berring retainer is larger on the big block but I want to know if the gearing is different.I have a 70 challenger with a small block and I have a 1973 a833 small block and just picked a big bearing retainer date perfect 1970 a 833 trans.I was told that you can bore out the small block bell to fit the big block trans but does anyone no of problems or will this effect my proformance?

crazy larry wrote:I know that the berring retainer is larger on the big block but I want to know if the gearing is different.

Non-Heavy duty 4-speeds had a 2.66 ratio first gear and a 1.91 second gear.

The heavy duty version had a 2.65 and a 1.93.

Both had a 1.39 and 1.00 third and fourth.

Not a lot of difference gear wise. The main difference was strength.

I didn't think there was any difference between them structually except for the input shaft -the 6packs and Hemi's and 440 with Trac pack (and maybe all 440 i think) got the 18 spline input shaft, while the SB and 383 got the smaller 23 spline input shaft and smaller bearing retainer. But other than that they were virtually identical other than the obvious change of extension housings between A, B and E bodies. They also had aluminium extension housings and some A bodies got the all aluminium case in later years. Too confusing trying to chase what was used where. And the gear ratios were changed quite often too between years. Later years (72 on i think) also used slightly different shift lever detent system behind the side cover.

Curious if a small block bell housing will fit to a 440.

Jon wrote:Curious if a small block bell housing will fit to a 440.

No way. Not without an adaptor. But it is possible to swap bellhousings .

I have this in my files. I don't remember where I got it, I assembled text and images from an article I caught somewhere on the web.
More than just 2 bearing retainers over the years, and some other differences as well.

Wow. That is great information Fabien.