....I just switched from 3:00 rear end gears to 4:11's. So I need to switch the gear on my speedometer cable. I went to a transmission site & it said I need the number of revolutions it takes to register 1 mile. I have Ford Classic Gauges & I'll call tomorrow & get this. Then it said I needed the drive or driven gear drive. Is this the number of teeth on the shaft in the transmission that turns the gear that I need to get??? I'm confused!!! I have a Turbo 400, 4:11 rear gears, 30" tall rear tires. Please Help!!! THANKS Bill