Gt 40 heads

[GT Rob]

I know that this question has been ask before but thay came off a fox's 50 would they fit a 95 5.0

 

[KillNThrill24]

My bet would be a 5.0 is a 5.0

Could be wrong but I'm pretty sure they are the same

 

[RichV]

Yes, they will fit. If they cam off a Fox, they had to have come off a 93 Cobra. They may not be originaly from a Fox, which would be SN 94/95 Cobra, 5.0 Explorer, or may be Ford Racing aftermarket.

They will bolt up and work. The differences between Fox and SN 5.0s is the emissions connections, not sure if it's a concern, but the Fox had ports in the back of the heads which you may need to plug.

 

[99GreenStang]

if it came off a 302 ( 5.0) it will fit any 302 simple as that also 289 heads will fit a 302 or 5.0 but thats a different story . Good luck man

 

[ttocs]

is it a GT40 or a GT40P's?

 

[99GreenStang]

both gt40 and gt40p will fit any 5.0 block only difference is exhaust valves and plug angle on them .

 

[GT Rob]

The headers match up also

 

[ttocs]

I know they will fit but the p's flow a little worse with teh smaller valves right?

 

[99GreenStang]

P heads flow better than the gt40 heads only difference is exhaust valve which doesnt matter that much. Gt40p heads are actually better heads than the gt40 heads people just dont like having to buy special headers .

 

[ScottyDsntKnow]

Ps have issues with plug wires getting burnt up, and some headers not fitting right. If I was going to do it all over again going from E7s to something else on a stock block I'd look to find a set of 3 bar GT40s off a Cobra or an early 5.0 Exploder, get them cleaned up, new springs, valve job, new guides, new seals, new retainers and new locks. Emissions won't matter at all on a 94/95 car as it is all external. Only thing that might matter would be the emissions ports on the back of the heads but you can either plug them or actually bolt them up and use them with the 94/95 emissions system. I'd plug them and the thread/pitch is the exact same as a spark plug. A lot of guys actually use old broken off spark plugs with some high temp RTV to block them off.

One piece of advice, don't waste your money on porting GT40s, it is a total waste unless you do EVERYTHING yourself. Paying to have them done is going to take these heads into the territory where you would be very close or even at the price of a good set of used aluminums which will murder the GT40s in every category while taking a good 80-100lbs off the nose of the car. Ask me how I know this lol. With that said, a stock 5.0 shortblock with cleaned up JY GT40s and Explorer intake and the stock cam with a S-trim is probably one of the best street combos in existence. With a stock block limiting you to 450-500whp safely there is 0 reason to go nuts on crazy flowing heads/forged rotating assemblies unless you enjoy lighting money on fire...

 

[99GreenStang]

On P heads the number 7 plug wire is the only one to worry about that takes a little engineering but considering the upgrade they are over the 3 bar 40's its worth it dont run away from a little work ! They make Fiberglass heat resistant plug boot covers I use a set of them with my P heads and no issues what so ever . Did double springs and hardened seats , viton seals on mine myself and the port and polish easy peasy .

 

[Addermk2]

I'd plug them and the thread/pitch is the exact same as a spark plug. A lot of guys actually use old broken off spark plugs with some high temp RTV to block them off.

Someone clearly hasn't got a clue what they are talking about...

Our plugs are 14mmx1.5 and the Thermactor holes are 5/8"-11.

All other arguments aside, if I was planning a supercharger or turbo build, I would certainly run GT-40 heads. That is probably why I have a set in my garage right now that have already been rebuilt with new guides, FMS springs/retainers/locks, and a full competition calves job. You really can't argue with the proven reliability of iron heads. If you aren't making an all out drag car, the weight drop from aluminum heads is irrelevant.

 

[ScottyDsntKnow]

Well I used 2 spark plugs for over a year on my old GT40s on my old 95 Cobra with copper RTV. Worked great. Empirical example FTW?

 

[Addermk2]

Well I used 2 spark plugs for over a year on my old GT40s on my old 95 Cobra with copper RTV. Worked great. Empirical example FTW?

Round peg, in a square hole. If you had used the correct pieces, you wouldn't have needed to silicone them in.

 

[CC'S95GT]

cross threading IS a form of lock-tite, right?

 

[LaserRed95GT]

Some clarification, but they're more than likely not Cobra Gt40s from a Cobra Foxbody since that would only be from 93' fox's.
If it's from another year and it's the 3 bar gt40s, it was taken off a 96 or 97 explorer 302. 97 to 01 I believe were the gt40ps.

 

[ScottyDsntKnow]

Round peg, in a square hole. If you had used the correct pieces, you wouldn't have needed to silicone them in.

Welp my spark plugs with the copper RTV worked, were free and I had 0 issues so yeah, from someone who has done it and had no problems... I mean have you done it or are you just recycling information you heard secondhand? I'm not second guessing the numbers, or that the sizing is a little off but not sure what the issue is running the spark plugs with copper RTV is. Especially if your local box store doesn't carry that pitch and you need to plug them to finish a build that weekend etc...


Anyway...

As for the heads themselves, its easy to tell multiple ways if they are Ps or not. Easiest way for the layman is just look at the bar markings on the end of the heads. 4 bars=Ps, 3 bars=regular GT40s. I'm partial to the regular GT40s as they don't require any universal plug boots, heat shields or potentially special headers. Also ran into the header and plug issues myself too when I did the Ps. MAC longtubes DO fit but require some creativity and the plugs boots needed to be universal and heat shields all on them. Blah...