GTP-40 head help! March 02, 2007, 05:46:28 PM Ok I have a slight problem. The engine I'm building is ending up with GTP-40 heads instead of GT-40 heads. The reason is that we (me or the machiene shop) couldn't find a decent set of GT-40 iron heads that didn't cost an insane ammount of $$$$$$. So now I have a problem. I'm guessing that with stock Mustang/MK VII headers my plug wires are going to hit the headers. So here's my question: is there any set of plug wires for the 5.0 that will clear the stock HO headers with GTP-40 heads or do I need to get some headers? If so what headers will fit so I don't have to hack the out of my motor mounts to get them in? Thanks guys:D Quote Selected
GTP-40 head help! Reply #1 – March 02, 2007, 05:56:40 PM BBK headers, and spark plugs for a chevy truck are known to work. Cougarman did that on his car.Personally, id do the BBK shorties, and buy some cut to fits, to ensure a good fit. Quote Selected
GTP-40 head help! Reply #2 – March 03, 2007, 07:45:23 AM I read some where I think one of these mustang web-sites that the stock stang headers will fit. Remember the 95 Cobra-R came w/GTP heads so if you can a least find a header off a 94-95 stang you will be alright. But they are very similar to fox headers.But my advice is since your doing your motor nice put a nice pretty set of headers on just before ordering check if there “p” compatible though most are now. Quote Selected
GTP-40 head help! Reply #3 – March 03, 2007, 10:15:44 AM Quote from: Innes;132216Remember the 95 Cobra-R came w/GTP heads so if you can a least find a header off a 94-95 stang you will be alright.1995 Mustang Cobra R's had the standard GT-40 cylinder heads with the 1.84" intake, and 1.54" exhaust valves.The GT-40P heads have a 1.48" exhaust valve.The only domestic production vehicle to get the GT-40P head was the 1996-2001 Explorer/Mountaineer. BTW, they made their first appearance on the Ford Racing catalog in 2000 (M-6049-P303)Brent Quote Selected
GTP-40 head help! Reply #4 – March 03, 2007, 03:02:25 PM I have a set of 1 5/8 unequal length mustang headers for mine,and the stock wires clear.Also i have the metal sleeves that the Mountaineer used to help with the heat. Quote Selected
GTP-40 head help! Reply #5 – March 03, 2007, 04:32:21 PM I have gt40p heads on my convertible and I would buy the headers designed to fit. I didn't put this together got a steal on the car last year and went to give it a tune up what a pain in the yin yang!! If I wouldn't have been short of funds at the time I would have changed them out then. Instead I'm building another engine with just e7's. I'm not real impressed with them anyway but, could be that the engine is just on its last leg lol. I would buy the header designed for them though. Will make life alot easier in the long run. Just my .02 Quote Selected
GTP-40 head help! Reply #6 – March 03, 2007, 09:49:09 PM I got MAC headers on Ebay for my setup. I haven't put it together yet but these headers are supposed to be for the "p" heads Quote Selected
GTP-40 head help! Reply #7 – March 04, 2007, 11:42:08 AM Well I'm just going to bite the bullit and pay $250 for the FMS stainless steel P headers at Summit. Actually with the headers it still comes out cheaper than getting decent rebuidable GT-40 heads:screwy: . On the bright side the heads I have are brand new and have never been rebuilt or used before. Quote Selected
GTP-40 head help! Reply #8 – March 04, 2007, 12:18:24 PM I have got a 98 Explorer engine with the P heads. I hooked up a pair of BBK Fox headers and the plug wires to use need to be 90 degree spark plug boots. Quote Selected
GTP-40 head help! Reply #9 – March 04, 2007, 10:31:29 PM I have two more questions for you guys. Has anyone installed the FMS GT-40P swap headers (M-9430-P50) and had a motor mount interference problem? I know people have had to cut their motor mount brackets to get the stock HO headers in but mine went in with no interference problem. I have about 1/4" clearance between the *U* bracket and the top bracket on both sides. I'm guessing that since these are 1&5/8" primaries that they will be a little bigger than the 1&1/2" primaries of the stock HO headers. I'm going to try not to cut the mounts so I might just, uh, dimple them if I have to so they fit:hick: .For those who have removed the thermactor system conneted to the heads (the GT-40P heads don't have the holes in the back of the heads and I don't have to pass emissions) how did you run the line to the cats? I'm leaving the air pump and cats on for now till I get a catless H-pipe and to work right they need the pump. Or do I just cap off the line to the back of the head? Any pics would help:D Quote Selected
GTP-40 head help! Reply #10 – March 05, 2007, 12:50:28 PM http://www.foxtbirdcougarforums.com/showthread.php?t=10125&highlight=header And as for the smog pump disconnect every thing and block it off at the cats. Real easy. Quote Selected
GTP-40 head help! Reply #11 – March 05, 2007, 12:59:13 PM Quote from: BCA;1322251995 Mustang Cobra R's had the standard GT-40 cylinder heads with the 1.84" intake, and 1.54" exhaust valves.The GT-40P heads have a 1.48" exhaust valve.The only domestic production vehicle to get the GT-40P head was the 1996-2001 Explorer/Mountaineer. BTW, they made their first appearance on the Ford Racing catalog in 2000 (M-6049-P303)BrentFrom my research the 95 cobras came w/GT40 heads but the same year 95 cobra-R came w/the GT40P this was to be the next generation 5.0 till emissions standards kill the push rod motor and they went to the 4.6 but the lucky trucks like explorers ect. got the latest in tech from the mustang engineers there’s a lot more to the story but another day. so my only proof is what I read but if you ever see a very rare cobra-R look at the heads. Quote Selected
GTP-40 head help! Reply #12 – March 05, 2007, 03:18:28 PM Hmm I'm not cutting my mount up. Looks like ball pean hammer time:hick:. Funny though that the passenger one fit fine but the driver's side doesn't. The header was only about 1/4 inch too low correct? If so I'm not too worried about denting the header. Quote Selected
GTP-40 head help! Reply #13 – March 05, 2007, 03:19:30 PM Quote from: Innes;132636http://www.foxtbirdcougarforums.com/showthread.php?t=10125&highlight=header And as for the smog pump disconnect every thing and block it off at the cats. Real easy.One more thing. Do you have a pic of the car with the FMS shorties on? Quote Selected
GTP-40 head help! Reply #14 – March 05, 2007, 04:45:18 PM Quote from: Innes;132637From my research the 95 cobras came w/GT40 heads but the same year 95 cobra-R came w/the GT40P this was to be the next generation 5.0 till emissions standards kill the push rod motor and they went to the 4.6 but the lucky trucks like explorers ect. got the latest in tech from the mustang engineers there’s a lot more to the story but another day. so my only proof is what I read but if you ever see a very rare cobra-R look at the heads.Well I don't have one real close but I do know of one that is about 150 miles away. A good friend of mine has a '95 Cobra "R", and a '93 Cobra "R" as well. Both of them raced in SCCA so they have a race history. I will give him a call. Quote Selected
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