I have a Ford Racing Cobra intake that I am planning on putting on my 1986 5.0 GT. The car is still speed density and has the stock injectors with a 70mm throttle body. The the car still has the stock heads, I have had several people tell me that the heads on an 1986 GT flow the worst out of all other model years. I have a chance to buy some GT40P heads but don’t really know too much about them, would it be worth the time and effort for the power that would be gained if any? Does this sound as if it would bee a good set up? Also I am hearing that the GT40P heads take special headers because of spark plug angle and also that the stock push rods on my car now will not work. Any information you guys would have would be great!!
Unless they are free I wouldnt use them. I have them you pay $300-500 then have to spend $125 on headers and $25 on plugs they do not perform for sh*t. I only have because they were new when they came on the motor. I will be selling as soon as my build is complete.
I'd have to agree that if you pay upwards of 500 for them than you paid too much, but there are plenty of them for low 200's, and although they aren't going to give any of the upper scale aluminum heads a run for their money they are solid heads for the money spent. Plenty of guys on this forum alone running strong with them(I did too). You have to buy headers anyways if you're starting from scratch, but the whole "special headers" deal is played out. You don't need "special" headers, you can either run the Ford racing shorties or the mac longtubes with no problems at all. The stock pushrods will be fine, but if you go with a cam (and you probably should) I would go with some hardened ones just for piece of mind. Overall if you do go with them you will have a notable power increase over your E6's. Here's a good thread with most of the info you'll need : http://www.allfordmustangs.com/forum...ke-thread.html
As an added note I put out 284 rear wheel horsepower and 327 rear wheel torque with the gt40p heads, explorer intake, and a trickflow stage 1 cam. Considering that stock these cars put down anywhere from 190-215 stock to the wheels I'd have to say they work.
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93 LX 2.3 to 5.0 conversion. 60% of the time it works every time.
VTEC - All the lag of a turbo............None of the boost
If its Fast and reliable, it ain't cheap.
If its Cheap and reliable, it ain't fast.
If its Fast and cheap, it ain't reliable.
Last edited by samotrx7; 3 Weeks Ago at 07:28 PM.
Reason: added info
Well now the big question is budget. If you are getting the heads dirt cheap they still should be checked and freshened up. You will also have to switch of the springs. If you do go with the heads and want that cam now you must spend some cash on a MAF conversion.
with a 86 you gonna want to keep the stock cam because of the different pistons, also I am doing a gt40p build with trick flow valve springs and 1.7RR's, the stock gt40p springs are bad, also you can run the heads on speed density with no problems, there also are a few speed density capable cams out there but with the 86 you would have to get the pistons fly cut, if you go on corral forums there are alot of people with gt40p's and stock cam running in 12's, and putting out around 270-290 wheel horsepower, there a good budget head. you will see alot of improvement of the 86 E6 heads.
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1988 mustang 5.0 LX, Edelbrock performer manifold, mac headers, off road H with high flow cats welded in, AC/smog eliminator, frpp 9mm wires, bbk CAI, msd cap and rotor, Flowmasters dumped, steeda tri ax, 3.73 gears, and mickey thompson DR's 13.91@101
1983 pontiac grand prix, weekend car, 355sbc 11.5.1, world heads, forged internals, th-400 with transgo shift kit, 8.5 rear with 4.56's and auburn posi unit, 11.96@115 on et streets. (SOLD)
If I run the GT40P heads will I have to upgrade to 24lb injectors or can I run the stock 19lb? Should I up my fuel pressure any from the stock 39PSI setting? I have heard that speed density set ups do not like bigger injectors.
so im not the only poor person here (jus kiddin)....i cant wait for my gt40p/upperlower intake tranformation, i mean for a everyday driver the 300hp mark aint bad especially for a cheap 1/2 build.
but yall are sayin to go with new springs and rockers?
---not to cut into your thread JT--- just wondering myself
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Most people hit the gas knowing they have reliable power, we just hit the gas and hope for the best.
so im not the only poor person here (jus kiddin)....i cant wait for my gt40p/upperlower intake tranformation, i mean for a everyday driver the 300hp mark aint bad especially for a cheap 1/2 build.
but yall are sayin to go with new springs and rockers?
---not to cut into your thread JT--- just wondering myself
Not necessarily rockers, but I would say springs are mandatory.
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93 LX 2.3 to 5.0 conversion. 60% of the time it works every time.
VTEC - All the lag of a turbo............None of the boost
If its Fast and reliable, it ain't cheap.
If its Cheap and reliable, it ain't fast.
If its Fast and cheap, it ain't reliable.
i have P heads and 19lbers..my A/F ratios are perfect across the board
12.71 @ 105.9 in a 3450lb convertible
maybe its just you? lol
Your time is impressive for the weight that it is. I worked with a guy that had a notch 347 that ran a 12 flat on all motor. He had a bunch done to it. Coil over adjustable springs, I don't think he had any traction bars, Eagle F1 tires, K member installed, was really nice and then decided to sell it. What gear ratio you running?
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"Pound for pound, the Ford Mustang is the best muscle car that money can buy."
3.73 gears and a 235/60-15 MT drag radial
motor trans and suspension is going into a notch roller this winter,along with some other goodies..should run consistent in the mid-low 12's..until i get a turbo or build a 408w haha
as far as the valve springs go,even with the stock HO cam i would upgrade the explorer ones..most likely they have well over 100k miles on them
i used the crane beehives # 44308-1,but they've been hard to find since cranecams went out of business
many others have used the trickflow kit from summit with great success..its about $130
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92 lx 5.0 vert-,stock plastic airbox,stock T-5,shifter & clutch,stock 19lb injectors and fuel pump,no radio,speakers or cruise control..antenna delete(for less wind resistance)
(new)best so far 12.712 @ 105.99mph 1.752 60ft
1986 Mustang GT - GT40P heads 
