I currently own a 1989 F150 with a 351w and a 3speed auto with what i think is a 3.55 geared rear. I'm going to be doing alot of Interstate driving and want to know what could be done to get better fuel mileage. Could I swap the current transmission for one with overdrive and if so, which one would be a direct swap? Any help is appreciated! I guess its the C6 in it now and would be looking at the E40D as a swap with the electronics coming with it? Is this possible?

thanks again.

 

If you want OD, the easiest way would be too swap in either a ZF or M5OD five speed. No change to the computer or wiring needed, unlike a E4OD swap. Also available is the non electronic AOD, but I wouldn't consider it behind a 351 unless built up.

Another thing to consider is a Gear Venders overdrive unit. Turns you C6 into a six speed.

Adrianspeeder