hey i got a 96 f150 4.9L 5 spd with a 3.55 rear end. A: how fast do you guess the engines spinning at 65mph (i dont have a tach and im estimating somewhere between 2800 and 3000). B: how much differance in gas milage, power and engine speed would a higher geared rear end really make and would it be work the work?

 

Should be somewhere around 2200 with stock size tires in OD with a .80:1 OD ratio. Dont know how much mileage you would pick up with changing gears though, sorry.

Steve

 

2200? really? that would be nice, it gets about 19 miles per gallon on the freeway anaways. im going to hook up a small tach to find out though.