rpm

[Mnstrstang]

One revolution of the tire would be about 3 and 3/4 of a turn for 3.73s, 4.1 turns for 4.10s and so on

 

[FaykSaleen]

Take your diff cover off, empty fluid and read what it says on the gears. Put diff cover back on (wait 24 hours if using silicone), fill fluid and drive.