Gt40p Blues Stuck In Da Stable.

Sheep Dowg

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Feb 7, 2018
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Greeting Stangnet,

This is my first thread ever. I feel like I’m posting wrong because there is lots of GT40P info in here. So here goes. My Stalions a 68 Coup, 90EFI, newly machined GT40P Heads, T-5 tranny with newly installed clutch cable. I didn’t do my resurch well enough as I have newly machined GT40P heads with Scorpion 1.7 rollers topped off with the 96 Explorer upper and lower that I have yet to fire up due to the lack of exhaust Headers. I have a MAC full exh with 1 5/8 long tube headers that fit awesome on the passenger side all the way back but the drivers side as you already know interfear with plugs and the ear on my newly installed clutchcable T-5 bell housing. So I ran across the really nice ceramic coated Sanderson FF3FMs. These shorties clear the plugs on the 5.0 but run directly into the clutch cable. I’m really after a MAC longtube replacement with the ball and flange. At this point all of your wonderful experience and suggestions should get me out of the stable!!
Thanx in advance for all of your help.
So here I go. I’m getting in, shutting up and sitting down.
My very best
Sheep Dowg
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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I moved your thread over to classic tech where the 2nd gen stang members hang, you should get some advice here.
Welcome to stangnet
 

Sheep Dowg

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Feb 7, 2018
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Please tell me I’m NOT the only 68 Coup that missed the Memo on GT40P Heads and headers? What makes this worse is I have the T-5 with clutch cable right in the way of my Sanderson FF3GTS GT40P block huggers that deadend right on top into my clutch cable. I know. Go Hyd. Well I just installed the quadrant and new extra length cable. Fits and works nice. $$$

I’d like to add for someone else out there that the STOCK 90 EFI Headers fit passenger side. I had to grind the flange on the Steering Box side to make it fit. Drove it for a good while like that. As a matter of fact the 90 H pipe fit right in using H pipe hangers at the tranny. Very nice. It did hang a bit low but nothing that created any problems. May have scrapped on 1 speed bump.
 
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Rusty67

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So it has been a while since I ran into this problem and it was on an automatic so there was no clutch cable issue. We just dimpled the header to clear the steering box and called it a day until we got custom headers made.

My advice is to find yourself a good exhaust shop locally and talk to them. Ask them if you can bring the car in and have them rebuild the driver side MAC header to fit and clear everything. A good shop should be able to do it without TOO much trouble and it should cost you less than a brand new set of custom headers. Besides, you are going to need some custom exhaust work to connect the headers to your exhaust system and get everything tucked under properly.

I've never seen a set of headers that fits GT40P heads with a clutch cable. Granted it has been a long time since I looked but it isn't the most common setup so I don't think there is a huge demand for it.

Also, if you don't mind, can you post a pic of the air intake setup on your explorer manifold? I put an explorer intake manifold on my friend's 68 and we make a custom intake pipe because we didn't have the stock parts so I'm curious what your setup looks like.
 
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Sheep Dowg

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So I went to 3 local shops here in National City & San Diego, the 2 in NC did not want to touch my MAC Ceramic coated header nor did they want to build a complete header. I assume they were just simple exhaust shops with minimal fab experience. Went to a famous 3rd shop I'll label as EH for initials, when I visited it was going thru new management/owners with new steep pricing and they didn't give me the time or day, just handed me a card and went back to talking amongst themselves. I didn't want to give them my money so I just felt that there was a set out in the Stangnet etc. world with my name on it. I've put together a combo that's not popular as you well know. I'd just as easily go AFRs but I'd still have the CC on the bell housing to deal with. When I started this project YEARS ago LOL my goal was everything stock using all of FORDs engineering prowness. Yah know, why reinvent the wheel. So here I am in a pickle with the new Explorer upper lower with newly machined and installed GT40P heads, newly installed Quadrant and longer cable and have not heard it run yet!! I worry as all my buddies said don't change a thing as its a fast Mo Foo. All these changes worry me a bit but I'm positively hopeful. LOL

Back to the MAC long tube headers I have that do NOT accommodate the P spark plugs on the Drivers side. Seems I really just need to either bit the bullet and order the FP long tubes for a nice cool G or go back to EH shop and see it they got there shop in order. Ughh Like you said I still need to spend money getting the Exh tucked up in there properly and that's additional over the FP Headers.

Let me get home tonight and get picts of the Air intake. It's nothing special. I'd love to see picts of yours as well.

This is good as it's putting a bit more fire under my belly to get this Stallion back on the Rd for Spring!! It's a 150,000 Refreshed, hone, rings bearings all stock with Explorer upper lower, 70MM? TB and 1.7 Scorpion rollers. I know all stock, Yah right. lol Stock 150,000 cam, that's stock! Ran plenty fast for me back when it had all the Stock 90 parts with the 8" 2:73 non posi. I'm hoping for a decent pucker factor after all is said and done!! New 9" with 3:50 Posi installed with Aluminum derive shaft out of a Police Interceptor.
 

Rusty67

15 Year Member
Dec 3, 2002
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I wish my friend's exhaust shop was still in business, I'd send you up to his place in LA but unfortunately they are closed now. My advice is to find an exhaust shop that has a mandrel bender and an upright band saw. Most shops are hack and whack, use crush benders and aren't qualified to build or even rebuild headers. If they look at a ceramic coated header and are scared of it, they ain't any good and aren't worth your time anyways.

I'll ask my friend to snap a pic of his intake, I don't have any.

Also, the weather in San Diego area is basically always nice. Why do you have to get ready for spring time, isn't it just always awesome weather? =-P
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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If you don't mind me jumping in here, what's the issue with the long tubes? I had long tubes with p heads and the plugs were close and a bit of a pain but doable, can you work around the LT's with the clutch cable?
 

Rusty67

15 Year Member
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Depending on the model of the header it will actually directly interfere with the spark plug and you can't put the header at all.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
I did mine in like 2004 or something, I think they were mac but really don't remember, they had the individual flanges, not the one piece, used the angled boot and insulators, there is also a short plug that I think accel makes but I haven't used them. Back then I couldn't find LT headers for p's, I had to have the LT's.
 

Sheep Dowg

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Rusty67, Your funny on the San Diego weather!! LOLOL that one hurt!! LOL I guess when yah get acclimated to an area yah become a Kitty Kat (P-ss-) LOL
I really just used it as a deadline to get the car done and its when the Clubs start to meet up. I go to one in El Cajon, Ca. weekly on Wed.

karthief, So there is a fella on YouTube that says he dispels the myth of GT40P heads and headers. Says yah the plugs are close but doable. Problem is with all these folks is everyone has a LT or a Shorty but no one knows the manufacture or part # so I just keep chasing my tail hopping . I just cant figure that as I see many folks that would use the P heads but no one wants to make em. I feel there was a market out there but then again all things considered AFR's or TW heads are way better. The fun/pain of the Hunt and success when you finally get your quarry.
 

Sheep Dowg

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Feb 7, 2018
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As requested. Full shot of air intake out of car.
CC28722A-9DE1-404E-97B7-DB11F551FDED.jpeg

Stock 1990 90deg snorkel into Explorer MAF
152B85BC-3D10-45A2-A78E-1EF381F22908.jpeg

Ok. Here I get ragged on and maybe why you asked to see my air intake. Good, ok Home Depot is Stang friendly with Chiter supplies!! I took my parts to HD and fit it all up. Got a 45deg and it all clamps up real nice. Good, tight and flexible. I did not use any glue! No need as I have the clamps. So much for keeping it stock.

36E7D0CB-EEFB-42AE-BF0A-C8CA5FF273EA.jpeg

Close up of MAF
6CC2C281-EA8B-4A7F-954D-55D0059A73B4.jpeg

She fits ok.
1F0E1D87-7D8A-4305-91A4-3BEBDF2FCF79.jpeg

She clears everything with I feel enough flex for engine movement. Engine bay is dirty but we’ll get her detailed when I get that header in. I have many more Picts. Just let me know what yah want.
A01FA39F-C2D7-41A3-A8FF-B54EFA7AD645.jpeg
 

Rusty67

15 Year Member
Dec 3, 2002
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Where did you get the shock tower brace? Did you make it or was it available from somewhere?

Damn it man, just order some pipe and silicon sleeves the right size!

Works in a pinch though lol
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
The thing with the p heads is they are old school hp, back when the gt40 and the gt40ps (explorer) were popular swaps there were not that many head choices and the ones you could get were expensive aluminum stuff and were not exactly plug and play. Now we have an array of choices from sve, edelbrock, afr and others that are bolt and go. Most say the few ponys you gain with gt40s or even ps are not worth the it when you could add more hp and lose weight for a few hundred more. When I bought my p's they were brand new with the updated springs good to 600 lift for 600 bucks shipped to my door and fit the what I was using my car for. I have the recites for my headers and I will see if I can find it.
 

Sheep Dowg

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Feb 7, 2018
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Lol. I love how Rudy’s busting my balls all the time. Lol. That didn’t sound good but hey. Lol. So I never thought of using the stock headers as the are the chocking point for this air pump. Every thought I had was get ride of them and flow this bad boy!! Well here’s some Picts. I believe I can at least get her fired up as my H pipe bolts right up to the headers and to my MAC mufflers. That is while I await the FP LT. Hmmm. What say you guys??

The Shock tower export brave is from Mustang Depot. Get some!!
I love it so far but I’ve not driven with it on. How’s that for Part #s info etc?? Lol. Even on sale!! Lol.
8C7B044E-D30B-4B73-A22D-B92D1E67AFE4.png


Proof we’re dealing with P heads. Lol
CE69D212-5D98-4C23-A7E5-E9CB5A5CE67D.jpeg

Passenger side stock header. Everything clears real nice!! Of course lots of room with those stock pea shooters.
001F77E9-7D8D-403E-AEF0-5FE6F722175C.jpeg

Passenger side boots on.
8CA5E90A-CFFD-4683-8A97-822C8AEE92E2.jpeg

Drivers side or shall I say Problem side!! Lol.
18C9C2EA-A91E-48FF-99E0-BE1716E05D8C.jpeg

#6 Cyl. Plug wire is all over it!! It’s worth a beating??
BE10B3C1-485B-487D-AECC-D448C68E31B9.jpeg


41080CAF-FF9A-41A3-AFAF-374F2D3E1BCE.jpeg

Boots on Drivers side. 6&8 Cyl very close. 8 better then 6 with a good smacking she’ll come around.
0AC94E48-D11B-478C-B183-08A18432083F.jpeg

#8 Cyl.
180FF8E6-B3A7-48F2-A829-DF9C7EDE74FD.jpeg


What say you fellas?
 

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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
Ok, I searched through the folder and found the info on the mac shorty headers for p's not the LT but I'm pretty sure they were also mac and I'm thinking they were from ebay. At the time I could not find LT's for p's. You want the part number for the shorty's? I doubt they are available anymore.
 

Sheep Dowg

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I'd love the part #. If anything else it will have all documentation here ready to go. And sometimes you can find a good old set on Ebay etc.
 

Sheep Dowg

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Look at you coming thru with the goods!! Nice!!
Here they are just like you purchased it seems.
3CFA320C-2158-443F-9096-0CA2A5775BE3.png
 

Rusty67

15 Year Member
Dec 3, 2002
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Seattle area, WA
So I just had a thought, which is dangerous I know. What if instead of using the P heads you used a set of 80s heads... which ones were those? E7TE heads I think? You could have Thumper port them out and they would out flow the P heads and fit your spark plugs. Although if you want to use the P heads it looks like you might have found a set of headers that work and at 350 for the pair, you are WAY cheaper than a head port.