GT40 -vs- GT40x

golden_eye

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From what I've heard about the Explorer heads, the 96-97.5 (I think) were the same GT-40s as the Cobras had, but not decked so they had lower compression (not by much though 8.8-1 or something vs 9-1). The 97.5+ have the GT-40ps which have the "Turbo Swirl" chamber and the smaller valves. They also have a different spark plug mount that requires special headers. It's true that the Ps have better flow, but from the charts I've seen the difference is borderline negligible.
 
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19COBRA93

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Hello? Did you read my post? The 96 Explorer heads are NOT cobra GT40's.

96 only, F67E casting (97-01 are F77E). Smaller "P" valves (Same part# from 96-01 on all V8 explorers, regular GT40's have different part numbers), smaller 58cc combusion chambers (higher compression) compared with 64cc on GT40, and regular spark plug angles, 96 Explorers have unique exhaust manifolds compared with 97-01.

I've owned all three and have been able to compare them side by side and know these differences first hand. This information is fact, not hearsay or assumed. I can back it all up with Ford part numbers if needed.
 
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CCM302

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Holy dead thread! I might have a warped head and need to replace them. Is the gt40x a direct bolt-on to a 93 cobra or do I need to buy other parts? Roller rockers? Specifically, I'm looking at the ones available on american muscle that are fully assembled (I think).
 

Blown_By_You

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Holy dead thread! I might have a warped head and need to replace them. Is the gt40x a direct bolt-on to a 93 cobra or do I need to buy other parts? Roller rockers? Specifically, I'm looking at the ones available on american muscle that are fully assembled (I think).

Holy dead thread is right. You are not supposed to revive old threads. Just start a new one

Sent from my DROIDX using Tapatalk 2
 

fivestangs

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Holy dead thread! I might have a warped head and need to replace them. Is the gt40x a direct bolt-on to a 93 cobra or do I need to buy other parts? Roller rockers? Specifically, I'm looking at the ones available on american muscle that are fully assembled (I think).

You'll be able to reuse the rockers (assuming you're talking about the rockers from a stock '93 cobra). I believe (and you should double-check) that the gt40x heads are drilled for 1/2" head bolts, so you'll need those little sleeves that drop in to the bolt holes so you can reuse your stock (or new?) 7/16" head bolts.

Why do you think you have a warped head? If you warped an iron head, you might have damaged the block surface too.....
 

CCM302

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You'll be able to reuse the rockers (assuming you're talking about the rockers from a stock '93 cobra). I believe (and you should double-check) that the gt40x heads are drilled for 1/2" head bolts, so you'll need those little sleeves that drop in to the bolt holes so you can reuse your stock (or new?) 7/16" head bolts.

Why do you think you have a warped head? If you warped an iron head, you might have damaged the block surface too.....

Yep, stock 93 cobra.

All of this is what Pep Boys told me...which I don't have 100% faith in. It did run hot momentarily (10 mins or less) a few times but it never red lined or overheated (my definition of overheating being that coolant is boiling out). There is oil leaking out of the front corner of the passenger side head. I don't have oil in my coolant or vice versa and I have noticed no performance loss. It may just be a gasket or head bolt not tightened down...but, I'm just preparing for the worst. I did some asking around of a local 5.0 guy that's been building and repairing them for a while. He said 5.0 heads don't just leak from a head gasket and that if it's leaking there's usually something really wrong. Maybe a ring, warped head or worse. I would be ok with just replacing them with stock gt40 heads too. It just seemed like if I had to replace them, the x heads would be a good bang for the buck and still look stock-ish.
 

CCM302

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Are you 100% sure it's leaking from the head-to-block mating surface and it's not just leaking from the valve cover gasket?

That's what I was thinking too. I knew there was something else I wanted to look at. Thanks for reminding me. Cause there's oil above and below the gasket and above and below on the head. And I don't think oil leaks up. I'll try to go and check on my lunch break and report back.
 

CCM302

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After further investigation at lunch, it appears that it may be head-to-block related. But I would have thought for sure that I would feel something wrong. There looks to be a head bolt (the very first one you see from front to back) that looks oily but i don't see anything underneath the valve cover that looks oily.
 

CCM302

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Or, maybe the intake manifold gasket leaking and seeping down. I see a puddle right below the intake.
 

CCM302

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I took it by a shop (owned by the ex-SVO/SVT guy for my local ford dealership). He said he's over 90% sure it's the intake manifold gasket and that it's no biggie. He also said it's rare that a 5.0 blows a head gasket even after being over heated several times. "It's alot harder to warp steel than it is aluminum" he says.
 

snakeplisskin93

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I agree its the intake. I had some minor seepage with my TW headed 90 GT. It's not a big deal and i would just monitor it and it never got worse. It would seep on top of timing cover like yours.

All the lower head bolts go inot the coolant passages,so you wouldn't get oil fom under them. The top head bolts are dead holes i believe.

Valve covers should be snugges up regularly or at least checked. They do work a little loss over time.
 

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