I have a 98 f150 4.6. After having alot of issues with cylinder 8 and not being able to fix the code. I went through plugs wires coils. After a compression test it was releaved that we have some internal problems. Probably a cracked valve as the spark plug was found damaged in orginal troubleshooting.

The truck has 1992-1998 standard heads. Can I replace those with the 1999-up Performance Improved (PI) Heads, without changing pistions?