Final drive ratio

#1

what would be the rpm difference at 70mph with a 3.23 versus a 3.73 on similar vehicles with same tire sizes?

#2

If the vehicles are IDENTICAL except for axle ratio, just divide the two ratios. Otherwise, no way to know without knowing the transmission ratios.

#3

Looks like an 11.5% difference in RPM at any speed. These sound like common Ford RWD ratios…

#4

I have it at 13.5% reduction 3.73(.135)=.503 3.73-.503=3.227

These are common GM rear ratios.