WELL I THINK THAT THE BARE HEADS WILL BE MY BEST BET AND HAVE THE VALVE AND SPRINGS PUT IN AT THE MACHINE SHOP. AS FOR THE PISTONS I DONT KNOW. SHOULD I WAIT TO AFTER I GET THE CAM BEFORE I INSTALL THE ROTATING JUST IN CASE I NEED SOME DIFFERENT PISTONS. MOST WILL EXCHANGE PARTS IF THE PARTS HAVEN'T BEEN USED. 550-600 WILL BE NICE BUT I KNOW TQ IS WHAT MAKE STREET CARS GET AROUND. I PLAN ON MAYBE IN THE FUTURE PUT A SMALL SHOT ON IT. WIL LTHAT EFFECT THE PARTS I BUY NOW AS FOR AS THE TOP END