The P heads if I recall, never had Thermactor plumbing. Seems I read that they burned clean enough to not need it.
You're right, I typed faster than my brain works... The factory P heads had a thermactor bump in the exhaust port, my Ford Racing P heads didn't have that.
You sure about that ? Seems to me the few P heads I've seen don't have any Thermactor features whatsoever, not even the bumps. I could be wrong though.
I ground off the bumps on the set of P heads I had. Not saying that they all had them, but the set I had did. GT40 heads also. I killed a set of GT40 (non-P) heads by porting them a touch too much and hitting a water jacket. So the second set just got the bumps knocked off and a little polishing. I am talking about stock iron heads here, not aftermarket or aluminum heads (which I think are called GT40X?).
The Aluminum heads came in several versions: The "Y", "X", "Z" that I recall. The "P" heads supposedly had revised exhaust porting, hence the use of the smaller valve, I guess that was BS if they still had the bumps.
Ok I am about to my breaking point on these headers!! they are such a PITA, I am thinking of going with stock exhaust manifolds to rid myself of the problematic headers and associated problems....decreased turning radius, frying clutch cables and just getting them back on the car, question now is what stock exhaust manifolds will work? I remember back some time ago they made both a right and left straight manifold, I have looked and can only find the passenger side straight back and the drivers side exiting a little over midway to the back, what are others using with no inteference issues?
I've got a left side 351W manifold I'll let it go cheap. No right sides though that I recall, unless one off a 97 F250 would fit. I have one of those on the 351 I pulled at the pick a part last year.
On another note but still on topic for this thread, the pushrods ARE NOT the same length from the heads I was using and the "new" heads, the new pushrods are a tiny bit shorter.
