[jumpsoffrock]

I have an SM420 4-spd Muncie. First gear is granny and is useless for real driving, but great for moving any damn thing you want.


Please keep in mind if you are going to be running truck-size tires(like my 22.5") that this will impact the gear ratio. 4.10:1 ratios will be quite high with such larg diameter tires and your engine may bog in the high gears with big loads.

It really depends what you're doing with the truck. If you are looking at making a 50 year old medium duty truck cruise at 80mph, I learned the hard way that that outlook is not reasonable.