906 head porting

if u want maximum horsepower go with aftermarket race heads. I had my stock heads magnafluxed, head gasket surface cut .010", 11/32" steel guides, 4 angle valve job for larger valves, backcut intake valves, did not need any new seats, cut for positive seals. blended ports and chambers and set springs and assembled myself. less $ than aftermarket and running great 20 years later