The mounting bolt relation to ports varied quite about on the factory heads. Same on the exhaust ports.
Way back in the archives there's a post by oldmanmopar about it.
We found it was also true when building headers. Header companies use one of several work arounds but they generally just make the holes sloppy big.
Anyway I'd do what Hoppy said. Compare with each head.
IMO First priority is seal.
Second is getting the top and sides so they line up or step down going into the head.