Yeah.. the more I read the more interesting things get. The D00E's aren't much better so I think maybe scrap that idea and wait till I read allot more. Seems like the GT40P are a better idea all the way around.
the plug angles are different(straight vs angled on the no P heads)... and they can be troublesome with headers not designed for them. from the few things I've seen and read.. not to mention the guys that I actually hear debating the issue in a parking lot(those 5.0 guys fight like chicks about this crap).. the P head has a better combustion chamber with improved swirl(and maybe more compression?) and slightly more flow in as-cast form despite smaller exhaust valves.. but the non-P head has more potential for porting mod's. I think it's a toss up between the 2 heads on a milder sub-350 horse motor and I'd buy what's cheapest while leaning towards to angle plugged GT40's myself. Servicability, header fitment, and room for growth down the road would be worth less swirl(slightly less mileage and low speed torque) to me.
Anybody know of a good buyers guide for head cast numbers? I'm not sure what the solution is and I'm not loooking to build moster HP. I would however like something a bit more peppy than the late 70's era smog crap. I'm liking the idea of the hydro roller cam with link bar lifters mated to roller rockers. I also like the idea of easy maintenance, I don't want to fight to change plugs like some of the new cars I've had.
I don't know of any guide.. but there are tons of dedicated 5.0 sites out there that may have stickies for something like that. Maybe try using their search functions to find it. As for the link bar styled lifters. Not trying to burst your bubble here.. but have you look at any retrofit lifters yet? They are PRICEY! You could quite literally buy a decent used roller shortblock and put a NEW cam and lifters in it for almost the same cost as updating an existing old one to a full roller setup. You'd probably still have some cash left over too! It sucks and many brands(my Chevy's mechanical AND hydro full roller setup cost me small fortune too) are dealing with the same differing lifter bore length issues as well. Small base circle cams.. blah! I'm not sure.. but I think there are retrofit kits that can make use of the factory style rollers and spider assembly with some block mod's. Even then though.. they are piced more expensive than a comparably equipped roller block setup. Maybe search around a bit and see what you'll get for the cash spent. If it gets too pricy.. you may want to consider restarting the build with a newer roller block. If you can find a 94 and up?.. you'll get the GT40/P stuff you were looking at included in the deal too. Good luck on the hunt.
AFAIK GT40P heads didn't come on the scene till early '97 in the Explorers, prior('96 & very early '97) had GT40... The Cobra 5.0 & Lightning 5.8 both used GT40 heads but those aren't nearly as common in the used market as the 40P heads... All port fuel inj passenger car 5.0 engines have roller lifters(this starts with '86), but other than the Stang & LSC HO all have poor flowing heads and wimpy cam...