Car ran slower then expected.

IF you are running a Gear Vender Over Drive, there's no reason you can't run a 3.91 or even a 4.10
What rpm are you running on the freeway with it in 3d and over?

crackedback, i don't know if you have ever use a G/V over drive but they Kick like Mule! The G/V is a auto clutch applying over drive. The pump is driven off the output shaft so it won't/can't engage under 20 mph.