alan,
for whats its worth, i have a rear out of a 1980 full size chevy 1/2 ton truck.
not sure what the measurement is from plate to plate, but it fits nice and on the original leafs.
i have 15x7 wheels with 4.5 back spacing with 225-70-15 tires.
but that full size rear is 5 lug with 5 inch bolt pattern.
the gear ratio is somewhere around 2:80-1, and with my 350 / th350 at 60-65mph i am right at 2200rpm.
if you need measurements, let me know and i will get them for you.
leonard
