In reality there is not enough power up front to handle a 3.55 gear in the back. Off the line you would be under powered you'd think the engine was a 4 banger.
What these old trucks need is more gears like a box with the normal low gears so you can accelerate but then have an overdrive so the RPM's can be brought down once you get to highway speeds.
I say this cause I have a 1 ton diesel,with a 5 speed and it it fine in all the gears but lacks the 6th gear to bring down the R's at highway speeds.
If I was to change the rear gear to bring down R's I would loose the power I need in the lower gears.
Guess that's why new stuff has 6 speed trans in them !
Dan
