I have made a living running Cummins Diesels for over 40 years. My Current favorite is the ISM set at 370 HP, 1450 ft. lbs of torque. However I have never had a real urge to have a Diesel pickup, even though I have a cousin that sells Dodge and Duramax. My current pickup is an 09 2500 HD with a 6 liter gas with single rears. I am currently cleaning out my salvage yard, and have hauled as much as 9,000 lbs on a bumper pull trailer and I can't imagine a Diesel doing any better. However, I would never consider putting one of these engines in a pulling rig for a camper. A 383 stroker would probably be an easier swap, because it would fit easier. But to modify the brakes, suspension, insulate the cab, etc. would be a long term project. A 28" trailer catches a lot of wind, and a 235 or 283 would be completely gutless. I would fix up the 58 to ride around in and buy a modern pickup to pull the camper.
