I will be using a lot of stuff from the first truck that was actually in good shape. The entire drivetrain will slide into the new truck. I have already taken the 350 completely apart and currently have it at the machine shop. It had a plug extender in the #3 cylinder, which meant either a leaking valve seal or broken rings. Turned out to be the valve seal. The rest of the engine was beautiful for being original 1971. No sludge buildup, rings were all clean, pistons were pretty clean.... only the timing chain was wore out. No pictures, though, as it was an oily, greasy mess. Sorry.
Other items to reuse will be the hood, everything on the dash, the entire interior, windshield and some small misc stuff.