OK I got my heads back from the rebuilder. Basic stuff, bronze guides, cleaned up the throats, new valves. Are the exhaust valve rotators needed? I assume that their job is to rotate the valve so that it does not constantly seal on the same spot.
Should I just scrap them and replace the springs and retainers with some aftermarket ones, or keep the rotators? It's a truck motor going in a J-20 for towing.