Since I am not a mechanic, my knowledge is limited here. But by reading on this site, sounded like the discussion was about gt-40p heads used on later model explorers with v8. they would probably have been equipped with the 302 and fulltime 4WD. You are looking to do this with a 302 correct? I guess my only question is if they do flow better, with your stock cam and speed density, what if anything would you get out of this. Course on the flip side the site also mentioned it is possible to find these heads at a scrap yard, seeing as there have been so many Explorers in production. the yards may not know much about particular heads on an explorer v8 motor (most would not think twice is my guess), so it could net you a real cheap way to try this mod.