It sounds like I will stay with the 72 heads. I already put some go-fast bolt ons and the engine ran good when pulled, so I don't want to open it up for just nominal gains. The 72 has bridged rockers and I don't wanna waste time machining anything, I am saving that for my 4.o stroker project, scheduled to start up again next month......Russ __________________________________ Start your day with Yahoo! - Make it your home page! http://www.yahoo.com/r/hs