As a general rule if the heads were shaved say .002 how much should the intake be shaved to maintain port match.
Thanks Mike

Wouldn't bother for .002".Factory machining was probably off by much more than that side to side. The rule is .0123" off the intake face for each .010" taken off the deck or head gasket surface of the head.

The number I remember from the DC book is .0095 per .010 on the deck. Is this number different between small and big blocks?

i'm thinking the .0095 might be the spec for removing 1cc of chamber volume ?
as far as i know, the .0123 on the intake face for every .010 off the deck surface is the same on both the big and small block engines.
that is so any intake can be used, and not locked into a specific head combination.
the amount needed to remove 1cc from a head chamber is more than likely speced for a particular head casting.
i'm sure more knowledgeable people will chime in with correct info.

.0095 is bb, .0123 is sb.....In my experience I just take the same amount. Think about it, if you take .030 off the heads your going to take .0285 of the intake a difference of .0015 (the other one would be a difference of .0069).
Now if you have aftermarket/ swapmeet parts, or a new build, your putting together the I would mock stuff up first, then adjust as necessary. Again those original specs would assume that you already had a perfect fit and wanted to retain that.

On the big block in you mill .010" from the combustion chamber side you would mill .0123" from the intake face and .017" from the block front and rear rails.

Thanks everyone for the replys

i forgot about the china walls !
thanks for pointing that out !
now when/if a guy were to use a 1/4" thick [or whatever thickness is standard fair] valley cover, would there be a different amount needed to be removed ? and would this amount be dependent on the particular valley plate ?
i agree with whomever said to mock up parts that whose history is unknown. you never know what has been done, and if you don't, surprises you won't like may appear !