Re: overdrive for a 39 120

Posted by Phil Randolph On 2012/3/15 6:38:04

Just some food for thought- I put an R11 OD unit in my 38 jr coupe and with 700R 15 tires 2500 RPM gives me 66MPH and that's with the standard 4:36 rear end. Right now my car has good driving power and I rarely have to "shift" out of OD for driving but with a 4:1 rear you MIGHT be going in and out of OD frequently if you live in hilly country.