I'm working on a 37 chevy project that I bought about 50% done. I need to identify the rear end and gear ratio to make sure it will be geared right for the 4-speed I will use. It is a 10 bolt rear end. there are no numbers on the axle tubes but the carrier has GM71 on the front passenger side and the numbers 3969340 NF on the front driver side. I tried to determine the gear ratio but I'm not sure I did it correctly. I marked the pinion and the tire. blocked one tire and turned the other one 10 times; the yoke only turned 13 times. seems to be very high geared but I'm probably not doing it correctly. I would appreciate any help.
thanks,
Tony