HP estimate

ctrout71

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Feb 2, 2010
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I just picked up a pair of bone stock GT40 heads from a 93 Cobra. If I put these on an otherwise stock 95 GT, what would I be looking at for horsepower? Any estimates on compression ratio? I will eventually upgrade the intake as well, just don't have the cash right now.
 
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What is the wheel horsepower on a stock 95? Will there be a significant felt gain in performance? The reason I ask is because I will not have the cash to get an intake until maybe the end of Summer and I am trying to decide if I want to put the heads on right away or wait until I can get the intake too and do them at the same time.
 
around 180-190

Balls on.

Sell those heads, they are worthless. You gain so little, it's not even worth the money changing out the gaskets. The money is much better spent porting your stock heads. If you port out the stock E7s vs. porting out the stock Cobra heads, the Cobra heads produce between 1 and 3 more hp at the crank. If you really can't afford a better set of heads, and you can't afford to port your stock ones, go to a junk yard and pick up a set of heads off a Ford Explorer. They perform much better than the Cobra heads.

If you put those Cobra heads on your GT as it is right now, you would most likely pick up nothing.

Kurt
 
I just picked up a pair of bone stock GT40 heads from a 93 Cobra. If I put these on an otherwise stock 95 GT, what would I be looking at for horsepower? Any estimates on compression ratio? I will eventually upgrade the intake as well, just don't have the cash right now.

Wait until you've got the intake and do both at the same time. You'll gain ~20rwhp. A port job on the GT40 heads and lower intake would really wake up the engine. The CR is the same as for the E7's in the GT (9.0:1).
 
Balls on.

Sell those heads, they are worthless. You gain so little, it's not even worth the money changing out the gaskets. The money is much better spent porting your stock heads. If you port out the stock E7s vs. porting out the stock Cobra heads, the Cobra heads produce between 1 and 3 more hp at the crank. If you really can't afford a better set of heads, and you can't afford to port your stock ones, go to a junk yard and pick up a set of heads off a Ford Explorer. They perform much better than the Cobra heads.

If you put those Cobra heads on your GT as it is right now, you would most likely pick up nothing.

Kurt

GT40's from the explorer are the same as GT40's from the cobra. Only the P's from the later model explorers are slightly better. And then you have header fitment issues.

And to the original poster I would just wait till you get the intake and do it all at once. This way if you have your heart set on using those heads you have time to get them ported.
 
Yes ... If you port up a set of E7's ...
they'll do better than non ported GT40's :nice:

But then again .........
What if you applied the porting burrs to the GT40's ;)

If you can swing it :shrug:

Save up for some nice flowing Aluminum heads :)

Grady
 
This is confusing to me. I have read countless claims of GT40 heads and intakes with the stock HO cam putting down 270ish RWHP. That's pretty much all I am looking for is somewhere between 250 and 300 at the wheels. If the heads only get me to 200, I can't imagine the intake delivering another 70HP. Are all of these folks mistaken or just plain lying? Here I was getting my hopes up. Kind of disappointing when my 6 cylinder 4 door Pontiac is faster than My GT Mustang with mods. The Pontiac hasn't sold yet, maybe I should keep it.
 
Yes ... If you port up a set of E7's ...
they'll do better than non ported GT40's :nice:

But then again .........
What if you applied the porting burrs to the GT40's ;)

If you can swing it :shrug:

Save up for some nice flowing Aluminum heads :)

Grady

That's what I'm talking about. If you do an equal amount of port work to either a set of E7s, or a set of GT-40 heads, the GT-40s come out with about 3 more hp than the ported E7s. The heads really aren't that different.

Kurt
 
This is confusing to me. I have read countless claims of GT40 heads and intakes with the stock HO cam putting down 270ish RWHP. That's pretty much all I am looking for is somewhere between 250 and 300 at the wheels. If the heads only get me to 200, I can't imagine the intake delivering another 70HP. Are all of these folks mistaken or just plain lying? Here I was getting my hopes up. Kind of disappointing when my 6 cylinder 4 door Pontiac is faster than My GT Mustang with mods. The Pontiac hasn't sold yet, maybe I should keep it.

The 95' Cobra, with the GT-40 heads, has a bigger intake, throttle body, and cam then the HO motor, and it has 245hp at the crank. Logic alone is going to tell you that putting those heads on a stock HO motor is not going to yield 270rwhp. When people are talking about putting down 270rwhp, they are talking about doing it with late model Explorer GT-40p heads. Probably heads that have been worked over quite a bit. The GT-40 name is used quite a bit by Ford, and there are many heads that have the GT-40 badge. The ones that came on Cobra cars suck nuts. There are the late model GT-40p heads that came off the Explorers, and at least two different performance aluminum heads; the GT-40 turbo swirl heads, and the GT-40x heads. The aluminum heads will definately get you to 270rwhp, but they cost as much as other performance aluminum heads that are better.

If you are looking for a budget H/C/I combo, get a set of Thumper Perforance E7 heads, and like a Trick Flow 1 camshaft. The cam is like $150, and you can get the heads from Thumper Performance for $699 I think. The heads are a bargain, they are fully ported and rebuilt. Who knows how much wear and tear the heads you got off a 93' Cobra have. You can pick up a late model Ford Explorer intake for about $100 on ebay, maybe a little more. You're going to have some nickel and dime items, like new lifters and a new timing chain, gaskets, etc. You will probably need to upgrade to 24lb injectors, which means a new MAF, or some sort of chip. If you get a decent size cam, you will need a chip anyway, so you might as well get the chip and skip the MAF. Thumper performance advertises combinations in excess of 300rwhp with these heads. I have become a fan of these budget builds, because the price of 5.0 parts has come down so much.

Kurt
 
Oh, and who pulled the stock heads off a 93' Cobra? Pray to god it was wrecked or something. Those cars weren't known for their performance, but they are worth a small fortune if they are all original and in decent condition. If someone pulled the stock iron heads off, and put aluminum heads on, they have ruined the value of the car.

Kurt
 
This is confusing to me. I have read countless claims of GT40 heads and intakes with the stock HO cam putting down 270ish RWHP. That's pretty much all I am looking for is somewhere between 250 and 300 at the wheels. If the heads only get me to 200, I can't imagine the intake delivering another 70HP. Are all of these folks mistaken or just plain lying? Here I was getting my hopes up. Kind of disappointing when my 6 cylinder 4 door Pontiac is faster than My GT Mustang with mods. The Pontiac hasn't sold yet, maybe I should keep it.
sure, you can get 270 with those heads, but you will also need a much better flowing intake and matching cam. the stock intake (especially te lower intake) is the biggest air flow restriction in our motors. and the cam doesn't have enough lift and is not open long enough to let enough air in to make much more than about 240 at the wheels