Cylinder Head Compatibility ? ?

Looking for reman. heads for my 1998 GP 3800 NA.

I'm trying to find out what casting numbers are compatible with mine.

Mine are #134 i think.

For example, are Buick #781's compatible?

What am I looking for, intake and exhaust port shapes? Anything else?

Thanks

Ian

edit changed casting number

well if u look at from this way if its supercharged the injector ports go into the heads and if its a gt the injector ports go into the intake other then that there all the same