Do you mean that if he changes to a higher gear, he will no longer be able to haul much ?
Yeah that is exactly what I mean. His truck is heavier than your car was, and his motor is a 216. While the 4.10 swap will likely work, going much higher could mean trouble. Not that it won't do it, but that it will be painful.
I once bought a truck with a 216 and a 3.42 rear axle from a guy who learned the hard way that the motor was not strong enough to move the loads any more.
GM didn't put 4.57 and 5.14 gears in these trucks because they wanted people to drive slow. They did it because these motors needed the torque multiplication to start and carry a load.
I've got a '55 1st 1/2-ton with 3.08 gears and a GMC 270. It will run 70+ on the freeway but don't put a trailer behind it.
