Southerner, I enjoy hearing from you in spite of the time difference. There was a time in the '55-'65 era when I recall a lot of articles in rod magazines about how to fit heavy duty manual transmissions like Cad, Lasalle or Packard to the "new" OHV V8s like SBC, Chrysler hemi and Olds to Ford bodies. At first folks with souped up Ford Flatheads started to put the new OHV engines in where the flathead was just with an adaptor to the Ford transmission. However those Ford transmissions were pretty fragile and could be shattered even by the Ford engines so they certainly did not last long behind a Chrysler hemi! However when the Powerglide two-speed proved pretty durable followed by the TH350 and TH400 the problem of fitting both clutch and brake linkage into early Ford frames made the idea of an AT desireable without the clutch linkage. So much for my biased view of history, the question of today is about the OD transmissions. I am surprised you did not find more discussion of the 700R4 GM or even the Ford OD units on the threads. I believe Tech1 has given some good information on the 700R4 and he convinced me that gives a good low gear as well as the OD fourth gear. Then there should be other threads on whether the 700R4 needs to be beefed up for engines over 300 H.P. There are articles on sites other than this Forum discussing the optimization of TH350 trans for racing, but maybe you can find some threads here on the 700R4 which I think is the latest trend slowly being adopted by rodders.

Don Shillady
Retired Scientist/teen rodder