318 exhaust port differences

I think the gaskets are key. They are touting the fit Ed heads, etc. Perhaps a more "generic" for lack of better set might fit "smaller." I had Hedmans on a ?70? 318 and don't even know what gaskets.......bolted 'em on forgot 'em

If I had to guess I'd say these were they

DODGE Hedman Hedders 27970 Hedman Header Gaskets | Summit Racing

Maybe you can call Summit and get lucky on a guy who can read a ruler