5.8 GT500 Trinity heads on Cobra 4.6 block???

04OWwhipple

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Are the heads from a 2013-2014 the same construction as the 05/06 Ford GT heads??? I know the FGT Heads take a little work to install on our cars. I have the opportunity to obtain a free set of loaded 2014 GT500 heads with cams and springs fully assembled. I believe they are the same casting as the FGT heads but am not positive. Does anybody know if that are the same head casting as FGT heads???


If so I will get these and put them on the shelf until I have time to put them on my cobra. Thanks!
 

04OWwhipple

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All 07-14Gt500 heads are based on ford GT heads.

This was my understanding so I'm glad to hear things to back it up.

You don't want them. better just send them to me lol

Hahaha. Well that almost tells me that they will work with a little effort and time. Tell you what, if I get into it and decide that I dont want to modify things that much to make them work I'll PM you.
 

98 Saleen Cobra

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This was my understanding so I'm glad to hear things to back it up.



Hahaha. Well that almost tells me that they will work with a little effort and time. Tell you what, if I get into it and decide that I dont want to modify things that much to make them work I'll PM you.
Sounds like a plan man. It’s a pita to make work with a top mounted blower. But yes please please let me know.
 

Nightmare302

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They have slightly different coolant ports on the front of the head. The gasket has a cut out for both. They also don't have the inconel exhaust valves.

Ultimately you'll find you have zero options in terms of intakes besides custom and using a PD blower almost impossible without heavy custom work.
 

badcobra

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Would cost a ton to run these heads with a supercharger, would need not only a custom intake, also custom headers. These heads would be best for a max effort turbo combination. Properly worked, the 03/04 heads can support huge power, mine makes 1600whp. I would LOVE to have a set of GT heads, but the cost to acquire them, port them, valvetrain, do a custom intake, redo the turbo hotside etc would likely approach $15k.
 

98 Saleen Cobra

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Would cost a ton to run these heads with a supercharger, would need not only a custom intake, also custom headers. These heads would be best for a max effort turbo combination. Properly worked, the 03/04 heads can support huge power, mine makes 1600whp. I would LOVE to have a set of GT heads, but the cost to acquire them, port them, valvetrain, do a custom intake, redo the turbo hotside etc would likely approach $15k.
Yea I’m looking to start on a turbo setup soon. I’ve been toying with fgt heads for a while. I can source the intake and I don’t have any other parts yet. It would be expensive in head work and stuff but my foxlake heads now would sell for good money I’m sure.
 

badcobra

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Yea I’m looking to start on a turbo setup soon. I’ve been toying with fgt heads for a while. I can source the intake and I don’t have any other parts yet. It would be expensive in head work and stuff but my foxlake heads now would sell for good money I’m sure.
They sure would be nice to have. Your Fox Lake ported heads would sell for about what a set of unported FGT heads would cost. It's WAY more money to do the FGT heads when you factor in everything, but if you're ballin, go for it! I sure as hell would lol.
 

04OWwhipple

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They have slightly different coolant ports on the front of the head. The gasket has a cut out for both. They also don't have the inconel exhaust valves.

Ultimately you'll find you have zero options in terms of intakes besides custom and using a PD blower almost impossible without heavy custom work.
This is what I still had questions on that I haven't found much info on, the cooling ports. I'm aware that they are different slightly but as long as the head gasket stay sealed the difference in coolant ports in not a problem correct??

I ask as I see you have a set of FGT head on one of your cars.

I am aware that the lower does not clear the intake ports without milling down the "ribs" on the bottom side of the lower.

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04OWwhipple

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Would cost a ton to run these heads with a supercharger, would need not only a custom intake, also custom headers. These heads would be best for a max effort turbo combination. Properly worked, the 03/04 heads can support huge power, mine makes 1600whp. I would LOVE to have a set of GT heads, but the cost to acquire them, port them, valvetrain, do a custom intake, redo the turbo hotside etc would likely approach $15k.
From what I have seen the stock lower just needs to be modified and milled "ribs" on the bottom side to clear which I can get done pretty easy. The exhaust, from what I can see, the flanges have a different bolt pattern but I think the ports are in the same physical location as our heads/headers. I will find out and if so I have a buddy who owns a fab shop can replace the flanges on my existing long tubes. A set of new headers flanges is around $75 from Kooks.

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badcobra

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From what I have seen the stock lower just needs to be modified and milled "ribs" on the bottom side to clear which I can get done pretty easy. The exhaust, from what I can see, the flanges have a different bolt pattern but I think the ports are in the same physical location as our heads/headers. I will find out and if so I have a buddy who owns a fab shop can replace the flanges on my existing long tubes. A set of new headers flanges is around $75 from Kooks.

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There is more to it than that on the intake side, the ports do not match up and there will need to be extensive work done to fix. You will also have a gasket issue to deal with. Not saying it can't be done, but just milling ribs is not realistic. Good luck with it though.
 

cj428mach

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I'm not on facebook anymore but when I was on there I saw a guy that was welding up the ports on an 03 Cobra intake and moving them to work with the GT heads.
 

98 Saleen Cobra

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They sure would be nice to have. Your Fox Lake ported heads would sell for about what a set of unported FGT heads would cost. It's WAY more money to do the FGT heads when you factor in everything, but if you're ballin, go for it! I sure as hell would lol.
Def not balling out of control lol. But I have nothing but time to do this.. I can source the heads, wait a year or more and have them ported and complete.. Find a intake etc. Still seems like a lot of work.. i'll just throw a 88mm on my current setup and make 1600rwhp lol. **** it
 

Nightmare302

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From what I have seen the stock lower just needs to be modified and milled "ribs" on the bottom side to clear which I can get done pretty easy. The exhaust, from what I can see, the flanges have a different bolt pattern but I think the ports are in the same physical location as our heads/headers. I will find out and if so I have a buddy who owns a fab shop can replace the flanges on my existing long tubes. A set of new headers flanges is around $75 from Kooks.

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The intake ports on a FGT/GT500 are massive compared to a C head and in a different location/shape. You'd need something custom to correct that geometry. It's hard to do because you need A LOT of material in the runner to be able to move the port that much and keep the runner.

I would not bother with them on a supercharged setup. No offense but the 40-50hp gained from GT heads on a PD car that will more than likely never even see 900rwhp isn't worth the thousands it would cost.

The best time to go GT heads on a 4.6 is when you go turbo and a custom intake.
 

Nightmare302

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I also no longer have my white car, it was sold to Stephen Floyd and then parted out when he finished his green car. I'm back on a 4.6 with C-heads and a Sullivan.
 

04OWwhipple

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Hmmmm.... well that all sounds definitely more involved than what I was thinking. I found this thread from quite some time ago and that's really all the info I found and it made it look much simpler than what you are describing so it may not be worth the time then

https://www.svtperformance.com/threads/ford-gt-heads-on-a-4-6l-pics.723984/

 

Nightmare302

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Hmmmm.... well that all sounds definitely more involved than what I was thinking. I found this thread from quite some time ago and that's really all the info I found and it made it look much simpler than what you are describing so it may not be worth the time then

https://www.svtperformance.com/threads/ford-gt-heads-on-a-4-6l-pics.723984/
You can see in those photos they had to do quite a but of work on the intake manifold to make it fit and even then I don't think I ever saw that car run.
 

GodStang

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Hmmmm.... well that all sounds definitely more involved than what I was thinking. I found this thread from quite some time ago and that's really all the info I found and it made it look much simpler than what you are describing so it may not be worth the time then

https://www.svtperformance.com/threads/ford-gt-heads-on-a-4-6l-pics.723984/


It depends what you mean as a lot of work. The lower intake has to have the ports opened wider to match the heads and the ribs filed down. Having ported aluminum intakes before it is super easy. Plus a few shops do this for not a bad price. As far as headers the easiest way is buy 8 Kooks GT flanges and have a shop weld them on. Also not that expensive.

The issues you may run into is the ports sit about a 1/4" higher on the GT heads which would sit your blower up higher. Depending on which blower this may be a new hood issue or K-member spacer.

Of course sourcing the heads and all the good stuff will be $$$. These cars in general are not cheap to work on. Having seen all the positive results of the cars over the years that have run PD blowers and GT heads I plan to run Ford GT heads if I can find a decent deal on them. Will the gains over ported 03/04 Cobra heads be worth it? Just depends on what you have invested in the end.
 

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