I looking at buying a used 86 5/4ton 4X4 chevy pickup. It has 4.56 gears, a 3spd automatic trans, 31 inch tall tires and the 6.2L diesel and @43K miles on it. I understand that the safe operating range for the 6.2 is between 1800-2800rpm. But what is the maximum safe rpm to be used for an extended period of time, like highway driving. The truck is located in PA which is about 4 1/2 hours from my house. With the 4.56's the truck has a max speed of @50-55 mph at roughly 2450-2750 rpm. Would driving at those speeds and that rpm be bad for the engine? Is the 2400-2500 @ 50mph ok? Before I lock myself into this truck I want to make sure I can even make it home to my house without doing 40mph all the way. I would like to use the truck to make similar trips to go camping, snowmobiling, 4 wheeling etc... and every place I go is at least 3-5 hours away. Will the engine handle 2400-2800 rpm for extended periods of time like 4-6hours of highway driving and not fail. Is that type of driving going to severly shorten the engines life span? I want the truck for it's ruggedness because it adds some piece of mind while bouncing around in the woods over 200 miles from home. Any help would be greatly appreciated.