Alum. head question.

[GMH454]

If they are from a L-89 they would be perfect for a good street engine.
Check that they have the winters snowflake, and the shape of the exhaust ports, If square they are right, if round, they are second gen, ZL-1 style heads, and benefit from high RPM big cam. Think twice before using them on a street engine.
I changed to them from good street heads, and was disappointed. Lost my bottom end torque.... round 4000 it gets to be fun, and it is a restored drag/street car, so that is okay, its just that the trip to the track will not be a lot of fun.
Good luck.