I'm kicking around doing GT 40 heads while I'm rebuilding allot of this car. I know there are about 1 million GT 40 Head Threads, but this had me curious. I spoke to a guy today who works at a "mustang" shop we talked about doing the heads. He suggested that I switch the car to MAS since it was an 88 so that the car could deal better with the increased air/fuel issues. The only thing I've read on this is dont do the GT 40 P head and headers and replace the valve springs. ????????