I'll add two cents in this discussion:
Any deviation from the original truck, in today's market, generally speaking will devalue the truck and not increase it. Obviously if you take out a oil smoking, grease leakin' rod knockin engine and replace it with one in good condition this would be an exception.
Visit Hemmings Motor News and Trader Online websites and look at values. The big money trucks today are the ones that are stock original and the ones with conversion and custom stuff are not able to bring as much money.
This is generally speaking. The quality of work in either case (original or custom) plays a huge role in the final value.
