The RC9YC is the same type of plug that I use in both the Eddy RPM heads and the Indy SR heads as well as I think they will work in the B1 as well as I have used them in the B1-BS heads They are a 14 MM plug size with 3/4 reach and 5/8 plug wrench size with a gasket and a protruded spark plug gap I have never ran any of the Mopar Stage 6 heads so