[jdorour]

You will want to choose your heads before you buy a set of pistons so you can select the piston the will give you the compression ratio you want (you should shoot for 9.0:1 to 9.5:1). The older heads have closed chambers and may need to be milled if they are warpedrequiring a piston with a larger dish.

If you are going to do the engine yourself you need to check each cylinder for round ness and taper. If any one of the bores needs boring you will have to do all eight and you will need to buy new pistons (and rings). If the cylinders are out of round or tapered you will never get the rings to seat.

You will also need to check the block decks for flatness. If the deck is not flat the head gaskets will not seal correctly and will not last.

Valve rotators are part of the valve spring retainer. They rotate the valve each time it is opened to aid valve cooling. Each time the valve opens and rotates it positions it differently on the seat when it closes to help eliminate hot spots.