Machining Intake to match decked block???

take the intake gasket it out...does it fit now....?

use the thickness of the intake gasket as a guide..

Right. And they make different thickness of gaskets so you might find some that are thinner that'll allow you to use the intake as-is.

BTW: Are you trying to use the cork end gaskets? If so try taking them out and setting the intake on the engine with just the intake to head gaskets and see how it sets. I bought an engine once that had the heads milled a bunch and when I tried to install the intake it wouldn't set down and line up so I took out the cork end gaskets and the intake set down fine then. I used RTV to seal up the ends and it worked great.