[Jack21]

Same with a T-5/351W. With 3.55 gears, and .80 5th, 75MPH is 2500RPM, which is right where I want it for highway cruise and passing without downshifting.

With taller rear gears, 3.73 - 4.10, you might want to use the taller 5th. The 351 with Cobra type cam and heads does like 2300 RPM or more at cruise.