Heads are at Machine shop for porting, larger valves, valve work (shop recommended by other posts). Question on drilling coolant passages through head fire face into water jackets. Information in, "Pruett" book is still correct? Use head gasket as pattern, in my case, Felpro head gaskets. Drill 5/16 inch hole, 1 inch deep. Four places on each head. No deeper than 1 inch or? Thank you for the help.
Steve V.
Steve V.