If you have a 29-31 cord with a overbore and get the idea of using V818 head gasket because it has a bigger bore, V818 is used in large bore 32 engines, they don"t interchange. V818 has 5 less water holes and a different bore spacing. Olsen's will be coming out with a V561, used in 29-31cord, with a larger bore in about a year.