I heard something about that but wasn’t sure if it was true. So is there special pistons that you’d have to use with the millennium heads? I’ve looked at a lot of old threads on here but couldn’t find much info on it. I just bought a set of 2 1/4 TTI headers and there for the stock cast head, now would they fit a stage 5 millennium head? How much needs to be changed to use them. I’m not even sure my pistons will work. Thanks for all the help.