I had a 350 in my 59 Suburban in front of the SM420 for years, I replaced the rear with a 12-bolt in a 3.4 gear ratio, plenty of power in granny to get it moving with whatever is behind it, and 90 down the freeway if you so desire. I swapped the SM420 out for an SM465 because it had a reverse light switch and was in better shape (SM420 had a noisy input bearing)
Last edited by 69Cuda; 01/11/2016 5:31 PM.
