I bought a 5.3 out of a mid 2000's silverado and planned to mate it up to the TH350 that was in the truck... though the TH350 needed a rebuild and a shift kit.
Heads were removed and planed smooth. Upgraded valve springs and replaced a few valves that had gotten a bit hot in the first 112,000 miles on this engine. I left the bottom end alone but swapped cam for a comp cams .534 lift 112 LSA unit that hot rod has used in a few carb build up. should be good for 415 hp. but we shall see.
I replaced the pan with an F body unit and a new double roller chain as well.
edelbrick intake and MSD controller box.
I also have a set of Sanderson CSLS1 headers to go on once i got it in the truck.