I don't know how any cylinder head and intake manifold port job could match up without using the block it's going to be on is used, with the head gaskets on. I'm glad I did my stuff that way or it could have caused a lot of headaches.
I guess if the manifold and heads are scribed to the outside edge of the intake gasket shape on the head it would make it easier.
I had my long block over at Tim's when I was trying to get my tunnel ram surfaced and that made for a little pita but it worked out eventually lol