If he reused his original cam and lifters in the bores they came out of he didn't have to break the cam in, though it would have been a good idea to rev it little to make sure they oiled up well.
Slow timing could be some of the overheating issue, and the engine would sound like it was laboring to run if the timing was very slow.
Make sure the valves are adjusted correctly and the plug wires are on the right plugs.
