That is actually a very good point, Jay. 108 RPM isn't going to make any difference, is it? I took another look at the rear end this afternoon, and it is in fact a 14:43 ratio (or 3.07). So at least the GM code book had it right.

I think the best thing is to see how it does with the 3.07 rear and the 4 speed and then take it from there. After all, 3.07 v 4.11 is a hair over a 25% reduction. As long as I've owned the truck, I've felt it was at the absolute least 20% over geared.

Thanks again for your help.
Jon

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end