[Daytona Dek]

Originally Posted by KarlzEE Bebout

Dek, it's unlikely that your differential will have a gear ration identification. Raise your rear end after blocking the front tires. Put the transmission in neutral. Make a mark on the propeller shaft and one on the inside of one of the tires. Count how many times the propeller shaft rotates during one rotation of the tire. The number of shaft rotations will pretty accurately tell you your differential ratio. EEZY PEEZY
If you do find that you need some rebuild/repair work on the differential, that would be a prime time to install some sort of positraction. Years ago I used a "Powertrax" unit that was easy to install (did it myself) and really did the job. It has no clutches so there will sometimes be a click or snap when turning while backing up. Not an issue, just different. The Powertrax was still in the car, 50,000 miles later with no issues. I'd dome lots of drag racing, turning 10.7 seconds in the quarter mile, after driving 75 miles to the track, and then driving home. My 2¢ worth.

Thanks KarlzEE for explaining the method for determining the ratio. It’s not difficult but don’t suppose it’s sensitive enough to determine all the ratios outlined in Ed’s reply. Certainly would be able to differentiate between say 3 or 4 though.
Thanks again.
Dek