Broke our 557 and decided to build a 598. This is a two part deal. (1)Currently running the Blue Thunder with raised Chev exhaust. Contemplating going to the a460 head. Will the same piston work for both or is the valve relief different. (2) Is there such thing as an adapter plate for the a460 to avoid buildin a new set of headers. Thx in advance, my hat is off to the guys that maintain and visit this forum. Info at your fingertips is worth money all day long.