Hello everyone just picked up my project 70 cuda how do I know what gear ratio actually came with the car decoded the tag and vin nothing thanks
That information is found on the broadcast sheet. If you have one.
If the rear end hasn't been messed with it should have a gear ratio tag on one of the carrier studs. Example pic snagged off the web
If the tag or broadcast sheet is missing or cannot be read, there may be certain clues.
What is engine size? What size radiator? Power brakes? Etc.
Also, if it is a non-A/C, non-340 car, then the rad cradle will help to narrow things down.
22" rad - most likely 3.23 gears (383-4, 440-4/auto, 440-6/auto)
26" rad - 3.55 or 3.91 gears (383-4, 440 auto) unless it was Dana equipped
26" 440-4, 440-6
- if automatic, then 4.10 Dana
- if 4 speed, but with manual drum brakes, then likely 3.54 Dana
- if 4 speed with power discs, then likely 4.10 Dana
if NO axle package is on the fender tag of a '70 'cuda (BS non-AAR) = 3.23:1 ratio & 8-3/4" rear axle
I often refer to the AMA Specifications.
https://www.hamtramck-historical.com/ama/_1970AutomobileManufacturersAssociation-01.shtml?load_img=1