My Dad's 70 GMC C2500 Custom Camper. He purchased it new in 1970.
Mods I've done:
RideTech Strong Arm rear suspension, bagged on all four corners, Weiand Supercharger, FiTech fuel injection, 20/8.5 Coys all around, power windows, seat late 90's Chevy truck, R700 Trans, 5 Lug with disk brakes, fuel door off late 80's Chevy truck, 20 gallon aluminum rear tank.
This truck has factory air, was never wrecked, all factory sheet metal, all original grille and headlight doors and spent most of it's life in southern California. Only rust was a very small amount on the passenger side rocker panel. Otherwise rust free.
Before:
After