It's pretty unlikely that just changing a couple bytes in the header is going to make your PAL ROM run correctly at 60hz.
Fixing that would require good ASM knowledge.
I wonder what game is it.
Here's a list of all the games I recognize from GameFAQs database to get a EU release but not US.
If I'm missing any, it's probably just more soccer games (or name variations of the many soccer games on this list).
I imagine only a relative few are probably worth playing.