I've got access to two heads E6SE and E7TE, which would be the better to go with??
E6SE = '86 Thunderbird. Chamber looks deeper but has a "pecker" between valves to bump compression. Supposidly the "real" H.O. head.
E7TE = '87 Mustang. Chamber looks much shallower.
My spec. book stops at '81 so I don't know which has the smaller chamber, bigger vavles (prob. same), or better flow.
This is the fourth damb engine into the BIII, hopin this'll be the last.

Go with the '87 head. It is the "real" HO head, and is the same head that was used on all the later model 302 and 351s in the F-Series trucks.

The "T" after the E7 is the giveaway, it indicate truck use, and the trucks got the HO heads.

The E7TE came off an '87 mustang. but if thats the case, shouldn't the 3rd digit be a "Z"? Or do the mustang / trucks share the same heads?

The Mustangs and trucks share the same heads, at least the '87+ 302s do. '86 was a funky year for the 302 motors, from what I recall they used a wierd head and flat-top (or was it domed...) pistons, that won't allow anything over stock valve lift.
But again, this is just my vague recollection at 6:50am with no coffee, so FWIW... :confused:
The valve sizes are going to be either the same or close enough to not make a difference. The E7TE head was used on the roller cam '95-'97 351Ws so it should flow plenty for a mostly stock or slightly modified 302. :smokin:

All non Cobra 5.0 Mustangs between 1987 and 1995 had the E7TE heads. Normally you can pick up a set for about $50/pair from most Mustang guys. That's assuming they don't just give them to you to get them out of thier garages. To most Mustang guys, E7 heads are really only good as an anchor for thier boat. They work relatively decently though for low power high torque applications. Porting the exhaust ports alot, and removing the valve guide boss which protrudes into the exhaust port will pick up nearly 20-25 hp with no loss in torque on the E7 heads. Spend three or four hours on the exhaust ports in those E7 heads and you will be pleasantly suprised. A cleanup on the intake side works well also, but is alot more time, and easier to screw up. It's nearly impossible to screw up the porting on the exhaust side, assuming you don't hit a water jacket. A more desirable head which is still pretty cheap, would be the GT40P head found on the late model Exploders. Only catch is the since the spark plug angle is odd, they won't work with most standard shorty headers. The GT40P's typically work with most aftermarket long tube headers though. The GT40P's are superior in every way to an E7TE. They both make more low end torque, and offer more power at higher engine speeds. If you can find a set for about $300 they are a great buy.

The 1986 5.0 heads were oddballs, as was stated above.

Do all '86 heads have the 'pecker' between the valves?? Dude sez that this makes them the true "HO" head. But on the other hand, he is trying to sell them. Kinda hard to believe some guys bosting about something that they are tryin to sell. Fu**in' salesmen :mad: