Aluminum heads

I would need to know more.... but fwiw
1008 felpro-.039 thick
8553 felpro-.046-.048 thick
519sd felpro-.054 thick

"Regular blue felpro" the 8553?
Try the 519sd and keep the good heads you have. If you were close...I could dial all the chambers in=enlarge them. I think you can fix this without changing something as important as the heads