Graflexmaster,
Here's a real easy way to check which rear axle gives more top end:
Chock front wheels n`jack a$$ of truck up a little bit so both tires ain't touch'in the ground. Get a rock or piece of wood & lay it next to one of the rear tires. Grab a bottle of your wife's brightest nail polish & paint a line on the rock & the tire. Effectivly, you want these 2 marks to line up like "timing marks". Then paint a line on the driveshaft & another reference point. Effectivly you want "timing marks" there also. With all brakes off & in highest gear, manually turn a rear tire 1 complete revolution `till the marks on the tire & rock align again. During that time, count the number of revolutions the drivesaft does. Write it down & do the same proceedure on the other truck, then compare the two numbers. The truck driveshaft that did the least number of revolutions is the one w/ the best "top end" for highway speed.
If ya really wanna know what the exact gear ratios are, there's a way that involves using math formulas added to this proceedure. Also you'll have to turn the wheel more than once.
CFFC
Don
