[underliner6]

The easiest route would be swapping the Denali’s Engine, trans, and case to the K10’s chassis. There is multiple companies that make LS swap kits including the crossmembers such as Dirty Dingo and Pacific Fab.

Doing a body swap is a major endeavor and why would you want to? The stock K10 chassis is fairly strong and with the Denali’s drive train would probably be fine pulling your toy hauler. Swapping the IFS from the Denali to the K10 frame would be a major PITA. Most would prefer to have the simple straight axle than the IFS with the additional moving parts on a classic truck. If you wanted stronger axles and better gearing for towing, perhaps look into some 3/4 ton or 1 ton axles from a 70-72 4x4 or square body 4x4.