Small Block Heads

4spdragtop said
Not for TA heads. I believe they have same casting number as X heads.
I could be wrong tho.

I dont think the TA heads were the same casting number as X heads. I think they were the same as the late 340 J heads / 360 heads.
As far as the origninal question, I wouldnt hesitate to mix and match the heads for a street engine.