The cheapo headers fit the E7 heads I originally had. But I had to heavily clearance the tubes of cylinders 2, 5, 6 to get them to bolt up. And I'm still burning plug boots on 5 and 6.
I hate to plunk down the cash not knowing if they'll fit.
gt40 heads have the same spark plug angle as all the other heads. Only one with a different angle is the P heads. How many bars on the front of the head? 4?
GT-40s are a direct swap for E7s. My Edelbrock 60379s are also a direct swap for E7s and I have regular smallblock headers for '65-73 289/302 Mustangs and 45° wire boots with no clearance problems.
100% sure. They have the three vertical bars and say GT40 in the valley.
I can assure you that they are not a direct swap. Have you had a set in your early Mustang that you've swapped directly? The reason I ask is not to be a a**, but b/c I'd like to talk to someone that has done what I'm doing.
The tri-ys fit on the e7's like a glove, with 45 degree boots. With the GT40s I had to almost completly crush the primary from #5 and lightly dimple #2 and #6 to get shorty plugs with 90 degree boots on.
Personally I think that the "direct swap" myth has trickled down from the fox 5.0 world - likely that all widely avialable headers for a foxes with e7s also fit GT40's but not Ps. Thus everyone assumes the drop right in for all body styles.
What shocks me is that I've had this same thread posted on this and other sites for days and despite the number of threads you see comparing GT40 heads to everything under the sun - there's yet to be anyone with iron GT40s on their early Mustang to respond. I thought this had to be the most common setup in the world. Go figure.
I run GT-40s in my '88 fox and use the Summit coated shortie headers. Fit is great and finish has stayed perfect for 2 years now. Absolutely no problems with plugwires.
I am in the process of swapping a GT-40 topend into my '68 and plan on using the same Summit headers.
I know you are looking for long tubes, but the shorties worked great for me
I have gt40 heads on my 65 Comet with Hedman 88400 headers, and no problems.
I know you say youre 100% sure you dont have P heads, but maybe you should take a pic of the front of the head to prove it to the rest of us. I had a set of unknown Hooker headers on some unknown 302 heads in my Comet and they fit great. Switched to Windsor Jr heads and they fit terrible (relocated plugs), then put the headers on a 65 Falcon with gt40 iron heads and they fit great. Heres pics of the Hedmans on gt40 non-P irons.
I found those pictures you posted in the Word docs. Looking at the chambers and the plug bosses, your heads are definitely GT40Ps or at least have the same plug orientation as GTPs.
I might be inclinded to agree with you if it wasn't for the stuff not captured in that thread - i.e. the three bars on the front of the heads, the "GT" casting, and the wierd off-sized plugs the head takes.
I will say that in the pictures that Decurion posted, those Hedman's on the #5 cylinder go down and then back. My tri-ys barely dip at all before heading straight back at the #5.
I guess you could have some weird early casting. In my searching I found mention of a GT40 head that had E7TE casting numbers and the raised "GT" letters by a spark plug hole.
Either way, the combustion chamber photos you posted look exactly like the GTP.
In your article on how to port heads you mentioned you had to buy new valves. What size were the exhausts? P heads have smaller valves than non-P heads. Im with 65Shelbyclone on this one. Youve got P heads. Maybe some oddball ones marked as GTs, but the plug angle and chamber volume both seem to say theyre P heads. Non-P heads have ~63cc chambers, and P heads have ~59cc chambers, which after milling would bring them to the 57cc you claim. Youd have to mill the non-Ps almost .050 to get them that small.
Okay, so I've finally gotten the camera cord and the pictures loaded to my computer. I haven't ever posted pictures on here, so the next few posts may get ugly.
The first shows the 3 bars and a little bit of the issue I have on #5.
Second shows clearly the "GT" casting.
The third shows the issues on #5 and #6.
I'll be damned if it doesn't look like I have the GT-40P plug angle. Look at the second picture I posted and then compare it to the pictures posted above. Look at how on the GT-40 heads posted earlier, the plug covers the "GT" casting, but on my heads, the plug doesn't seem to cover the casting.
WTF heads do I have? Has anyone ever seen this before?