I know this is an old thread, but I found a source for the correct size '68-'77 Pontiac 350 head gaskets/set. Just received a ROL gasket set for the Pontiac 350 that has the correct size head gaskets. Contact: Competition Products, 280 W 35th Ave. , Oshkosh, WI 54902-7173 or
www.competitionproducts.com
The part number is INS71884-1 for a ROL gasket set.