A few questions about GT40P heads, please help.

Discussion in 'Fox 5.0 Mustang Tech' started by astronut1885, Dec 18, 2003.


  1. astronut1885

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    Hey guys. I am going to be pulling an Explorer intake off of a 97 5.0 Explorer motor. The intake has EGR, so I was told that the heads may be regular GT40s. If they are not, and are GT40Ps like many suspect, would I be able to use them with my MAC 1 5/8" HTS coated unequal length shorty headers? I could get the heads for 300.00, but I can't afford nor do I want to buy the special FMS headers. I know some guys have said that their long tube MAC headers work, but I want to know if I would have any problems if I tried to swap them in. Also, these heads are coming off a truck that had a bad fire, most of the engine bay was cooked. Is there anything inside a head that a fire could destroy? Finally, would I run into any problems putting these in a speed density car? Thanks for your help guys :hail2:
     
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  2. astronut1885

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    Come on guys, I know people know about this...
     
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  3. Michael Yount

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    If the Exp. had egr internal to the manifold, then the heads are GT40's, not P's. P's with regular headers will pose spark plug access problems - You can use them, but you'll have to take them off to change spark plugs. I wouldn't touch the heads off an engine compartment fire vehicle for any price, let alone $300. There are too many other alternatives. Leave em alone.
     
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  4. astronut1885

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    The intake would be ok though, right? What could be wrong with the heads? Thanks for the info Mike.
     
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  5. cmclean

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    Being as the intake is made of aluminum, I would be concerned about it being warped by the heat from the engine fire.
     
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  6. Michael Yount

    Michael Yount Advanced Member

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    I'm with cmclean - unless you can get this stuff with a money-back if anything's wrong, I'd look for another source. As for the heads, depending on the heat, the valve seals could be bad, not to mention, it just wasn't on the engineer's punch list for the head/intake to be able to withstand a flame test in the engine compartment and come out untouched. More than likely, it's all fine -- but I wouldn't take the chance without an iron clad money back guarantee. There's too many other options/parts/alternatives available to feel like you've got to jump on this stuff. Just my opinion.
     
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  7. astronut1885

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    I can get a money back guarantee if they are defective, my friend/mechanic is the manager of the JY that has this truck. The fire inside the engine bay wasn't that bad, the wires behind the intake still have their individual insulation. The main area of damage was where the battery was, through the fire wall, and into the cabin. The left side was not hit bad. I was told that if I didn't end up liking it, or it didn't work as I wanted, then I was screwed, but if the intake was warped or otherwise damaged when recieved, then I could bring it back. I'd imagine that the same would be said for the heads. I would like to talk him down to 200.00 for the pair, though.
     
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  8. 92BlackGT

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    Sorry to butt in and ask a question.
    But, how much power will the car gain by putting on GT-40P's with a Cobra intake, 73mm maf, headers and h-pipe???
     
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  9. astronut1885

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    Not sure, but the heads are a big power maker, even on a stock motor they are a bottleneck. I'd imagine that all of those mods on a stock motor would give around 100HP, but that's a speculation. If you are gonna do all that, I'd add in some U/D pullies too, nice power gain on those...
     
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  10. astronut1885

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    So, what would I look for on the heads to know if they are damaged? They look only scorched on the outside and in need of cleaning. I just don't want to waste my time installing heads that turn out to be bogus. Give me some things to look for on them. Thanks guys.
     
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  11. Michael Yount

    Michael Yount Advanced Member

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    As I said earlier, I'd look elsewhere. But if you feel like this is your best bet, I'd take them to a reputable automotive machine shop, explain the history, and ask them to take a look at them for you. They can check them over. You'll have to invest a few bucks....
     
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  12. astronut1885

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    michael, please take a look at my new post about the GT40Ps. I found new ones for 200.00 that aren't crispy. I want to know if my MAC shorty headers can bolt up to the GT40Ps. Thanks again.
     
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  13. Michael Yount

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    The fitment issue with headers has to do with the way the spark plug is fitted in the P's. Regular headers will "bolt up to the GT40P's". But most folks find that either they can't get a spark plug socket on the plugs to remove them, or they have problems with wires/boots being too close to primary tubes. Every now and then someone will say "I used brand X header and it was ok". But I've yet to figure out if 1) they got lucky 2) Brand X was designed for both P's and the rest of the heads (Ford Racings new shorties are) 3) they changed the boots and made/found a special plug socket 4) ??????

    So you see I think the facts support the notion that the P's will bolt on, and that you're likely either gonna have spark plug access problems or wire/boot melting problems or both, and every now and then someone finds a way around that. If you're looking for certainty that your headers will work, I don't think you'll know unless you try - so there's risk. If you absolutely want to eliminate the risk it seems to me that you either have to buy P-specific headers or don't buy the P heads.

    That's the best I can do in response to your query. Good luck with whatever you decide.
     
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  14. astronut1885

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    Thanks Mike. I am not worried about access problems, because if 25HP comes at the cost of pulling my headers every other year, I am cool with that. As far as melting wires, supposedly 90* wire boots make it out ok, and if you put on some kind of heat boot over them, they do better. I just wanted to make sure that they'd work barring the spark plug problem. I more than likely can not afford the P headers right now, but later on I will get them when I have extra money, and sell my MACs for whatever I can get...
     
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