hey im contimplating buying a set of gt40p heads, someone recently told me there not that good although i had heard earlier they were a good choice of heads for relatively stock cars...is there a difference between gt40 heads and gt40p heads? What do you guys think?
GT40 irons - came on the Cobras 93-95 and the Explorer/Moutaineers from 95-early 97. GT40P is a different head - came on the 97-2000 Explorer/Mountaineers. The combustion chamber is more efficient, slightly higher compression ratio from a smaller chamber. The spark plug is at a different angle, so most folks have to run different headers to access the spark plugs -- in other words, you have to buy a P-specific header for that head.
There are also GT40Y, GT40X and GT40Z heads from Ford Racing - all aluminum.