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Discussion Starter #1
I Got these heads today for a steal! So if they dont work im not worried i can make my money back X3.. I have heads off a 96 5.0 explorer (gt40) will they bolt on the same for my 94 302 Bronco? i heard smog might be a problem? let me know! thanks
 

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I got a set off a 96 (I think) Moutaineer and they bolted right up on my 1993 5.0 The set I got did not have the holes in the back so I didn't worry about it. Ended up gutting my air pump and disconnecting everything else.
 

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Eric
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Some of the earlier GT40 heads that came on the Mustang Cobras and Lightnings (i.e.-F3ZE-AA) just had "plugs" in the thermactor port trunk-line. These can removed fairly easily. You need to check the exhaust ports for the outlet holes, though. If there are no outlet holes present in the exhaust ports, then, your GT40 heads are not thermactor compatible.

Also, I have done some research and have found evidence that only one casting/machined head was made for, both, the Cobra (5.0L) and the Lightning (5.8L) for the 1993 model year. So, to save on machine work, Ford drilled all the cylinder-block-to-head holes at 1/2". Therefore, if you are bolting these heads onto a 5.0L, you will need the tapered bushings that allow for 7/16" bolt installation. The Cobra "head-bolt installation kit", from Ford back-in-the-day, came with these bushings. The info. I found could be wrong, though, so somebody please correct me if this is inaccurate.

Machining can remedy the thermactor issue, but, after being shot down by several engine machine shops because they did not have a drill bit/jig long enough to drill the main trunk-line, I had to find an aerospace machine shop. The extra-long drill bits cost ~$40 each and the shop needs to be able to jig up the heads so the holes can be drilled in a single pass. The bit, IIRC, needs to be over 17" long. I did this on my GT40P heads off a '98 5.0 Explorer.

However, I also have a set of earlier GT40's, casting # F3ZE-AA. They just had the plugs that need to be removed and the, individual, outlet holes in each exhaust port were, already, present. Direct bolt-on after the plugs are removed from the rear of the heads. Both ends of each head are plugged, so, decide which end of the head you want facing the fire-wall and remove those plugs only.

My $0.02,
Eric
 

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Eric
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If you don't need to pass smog, then, just delete the thermactor system. I don't know the specifics of how to do this because I opted to keep mine intact to pass emissions. There are others, here, who know how to do this and not have the computer throw codes or light the CEL.

If you want to keep the emissions equipment, in its stock form and functional as such, then you need to start contacting machine shops to see what they can do to modify the heads to be compatible.

Otherwise, find a set of earlier GT40 heads with the ports. Mustang Cobras and Lightnings are your best bets for this, IMO. Again, if it helps, the casting number on my set is F3ZE-AA and they have everything to work correctly. I, simply, had to unscrew the threaded plug from the back.

Eric
 

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Discussion Starter #7
If you don't need to pass smog, then, just delete the thermactor system. I don't know the specifics of how to do this because I opted to keep mine intact to pass emissions. There are others, here, who know how to do this and not have the computer throw codes or light the CEL.

If you want to keep the emissions equipment, in its stock form and functional as such, then you need to start contacting machine shops to see what they can do to modify the heads to be compatible.

Otherwise, find a set of earlier GT40 heads with the ports. Mustang Cobras and Lightnings are your best bets for this, IMO. Again, if it helps, the casting number on my set is F3ZE-AA and they have everything to work correctly. I, simply, had to unscrew the threaded plug from the back.

Eric
ok thanks buddy. Yeah this isnt my daily driver so im gutting the smog and everything after im done with this engine build.

Now will my 302 lower intake bolt up to those heads. Ive been hearing a few things with people saying the lower intake WILL bolt to it but the ports dont line up is this true?
 

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Eric
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GT40 heads are direct bolt on other than the missing ports on the back. unless you have a 351 in which would need the headbolts drilled bigger
My GT40's came with 1/2" holes and I wanted to know why since it was sworn to me they came off a Cobra Mustang. I have read (but don't know how true it is) that the early GT40 heads were designed to work with the Lightning (351W) or Cobra Mustang (302), so, the heads were drilled with 1/2" holes from the factory. I know, from personal experience, that the stock head bolt "kit" from Ford a while back, for a '93 Cobra Mustang, came with bolt bushings included in the package. This would lend some truth to what I found out in my research. However, I don't know if I buy it, or, not.

Again, I don't know if it's, entirely, true or not, but, it's true for me. :shrug

Eric
 

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September 15 FOTM
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I put gt40 heads on my 351. I pulled both them off the same 96 explorer, one head already had the holes drilled to 1/2.. I just deleted the smog pump. Also you need different plugs, at least the 351 plugs don't fit. But everything else bolted right on
 
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