i checked my casting # 4838302----->does this mean fast burn,swirl,heart shape design......i dont ming grinding...if I PORT MATCH THESE WITH 340 GASKETS,UPGRADE THE VALVES....WILL I BE GOOD WITH FLOW. MY 340 BLOCK PURCHASE CAME WITH TRW.30 OVER PISTONS.....ASSUMING I DONT NEED TO BORE, I WILL USE THESE PISTONS.
