The 428 is just a factory stroked 400. Even had the same bore dia so only the pin height is different. The factory used dished pistons so factory 400 heads were used on all 428's and got the same compression ratio. Not sure what 'extra' stuff there is to it in addition to a routine rebuild over a 400. I have not piston shopped in a while but I would be surprised if they cost much more than any quality dished piston. Or, get another set of heads that will get the compression ratio where you want with flat tops. Cast iron heads are cheap and plentiful. 428's use the larger crank journals shared with the 421 and 455 but there is no significant extra cost there. Anything else you decide to do extra is just that, extra. They came with and accept all the same V8 (326-455) stuff. I love my 428, had it since high school.