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Discussion Starter #1
hey guys i have a 390gt fe motor in my 67 mustang,i bought jb8 headers when i first built it 5 years ago with 16 bolt manifold flange that matted to my original c7ae heads,obviously all lined up except for the two bottom manifold bolts cause they simply arent there. the original heads have only 14 bolt no big deal ,now i decided to want more power so def aluminum heads are the goal,which heads can i buy does any fit with my header or i have to buy specific one due to the fact there gt headers cause i know the port or bolts may not line up,no one seem to really know im going craxy here for a answer PLEASE HELP
 

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Ponta6, what brand and what part number headers do you have now ? Whats your camshaft and your intake manifold ? LSG
 

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hard to believe they could ever seal at the top of those ports. I don't remember the port location differences but it looks like you had a miss match because those couldn't have been sealing. Probably need a cj head port to make it work.
 

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My '67 390 had Edelbrock heads which used the mid-rise intake gaskets and Hooker Super Comp full length headers. The headers sealed fine but hung too low for most speed bumps. Had I kept that car, I most likely would have upgraded to FPA's which tucked nicely between the front sub-frame rails and allowing a significant improvement in ground clearance.
 

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What is your HP goal? You racing it?

I have a 67 with factory 390 4spd and my goal when doing my resto was mostly stock but little more HP. I didn't want to deal with headers and some of the issues.
So besides adding Ford tri-power set up, I went with Edlebrock RPM aluminum heads ( which at the time not drilled out for stock 390 exhaust manifolds, but since are?) I decided to find an orig set of SCJ exhaust manifolds for which the heads are drilled for. Had all mating surfaces machine planed so not gaskets required. BTW the SCJ manifolds have rather large ports, bigger than stock 390.
So with tri-power and little larger exhaust, I'm happy for weekend driving. Car being a vert and exhaust pipe size limited thru trans tunnel, it's ok
 

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Discussion Starter #7
hard to believe they could ever seal at the top of those ports. I don't remember the port location differences but it looks like you had a miss match because those couldn't have been sealing. Probably need a cj head port to make it work.
yeah thefit np and seal have had them for 4 years now np
 

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Discussion Starter #8
so in that case cani use any type of aluminum heads ?and how much of a diffrence does it make since these motor dont breath much
 

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Replacing exhaust manifolds with headers and then heads w/ Edelbrock's are probably the 2 biggest HP improvements that you can make to an FE (then cam/valvetrain - snowball affect in affect, ha). Byteme is correct that the Hookers have ground clearance issues. FPA's are the way to go. You can call Stan @ FPA and he might help you. Then again, he'll probably try to sell you a set of his headers.
 

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yeah thefit np and seal have had them for 4 years now np


Theres a drawing on that page of the exhaust port height differences. I just suggest making sure yours matches your headers or more than likely you'll have leaks.
 

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Those headers wont fit the edelbrock heads. The two upper end bolts will be lower than the ones on the edelbrocks. The exhaust ports on the edlebrocks will be higher up than the 390 heads, and even if you didn't use those upper end bolts I doubt it would seal as the port will be right at that bolt hole. Hers a pic of a 390 header and a 428CJ gasket (which is the port the edelbrock uses)
 

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Lok into the new Trick-Flow big block Ford aluminum heads.
 

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Ponta6, I think you should keep the headers, but they need a little work. First, I'd weld up and dress some of the wld bead that is supposed to seal the top of the exhausts. Then, I would make all eight upper and lower holes slotted, with open ends, on both headers. Then your header will let the bolts be wherever they need to be, with the alignment dictated by the diagonal bolts. Are aluminum heads available with the lower exit exhaust ? Or is it time to consider different headers ? LSG
 

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All the aluminum heads I’ve seen have the high exhaust port......
 

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Discussion Starter #15
so i go toff the phone phone with elderbrock tech there saying that they have there aluminim heads that will fit my setup np due to the fact i have headers they fit?does anyone have other suggestion onwhich aluminm head to get trickflow,blue thunder ?who got the best performance?
 

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Ponta, has the Edelbrock tech seen the flange on the headers you have ? I think the Eddys might well fit, and others might as well, but your headers need some work. LSG
 

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Discussion Starter #17
Ponta, has the Edelbrock tech seen the flange on the headers you have ? I think the Eddys might well fit, and others might as well, but your headers need some work. LSG
Ponta, has the Edelbrock tech seen the flange on the headers you have ? I think the Eddys might well fit, and others might as well, but your headers need some work. LSG
i send them a pic of my header he said it will but i never trust these guys
 

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Here's a pic (not mine, just saved from another FE Forum member because this comes up a lot) maybe it will help. It shows the port location of what your heads have now vs an Edelbrock head. As you can see the Edelbrocks (and 428CJ and early pre 66 heads) have an exhaust port that is about 1/4 inch higher up. If the top of the opening of your headers is that distance from the bottom of the head you could take them, have the top end holes welded up and drill new holes higher up. I think those upper end holes will be right at the top of the port leading to a poor seal. Looks like they are already in the sealing area for the low port heads.
Hope this helps.
 

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