Hi not sure if this is the right spot for this question but here goes. I have a 1973 smog dog 455 with the big air rails and egr valve and I want to de smog it. My options are a 360 Offenhauser manifold and a 4brl manifold off a 1970 455 GS. So can ether of these be made to work on the 73 heads. Thanks.