I just gasket matched the heads (973 smog head) for my 318 to a felpro 1243 intake gasket which are for the 318 2bbl heads. Gasket openings are 1.05" x 2.08". These gaskets match perfect to the Performer 318/360 without gasket matching.
Hopefully I'll pick up a little on the 318 by doing this.:burnout: