Gt40 heads and Cobra intake

cmozez · Sep 5, 2008

I have a set of Gt40 heads that I am going to home port, a Cobra intake that I am going to have Tmoss port the lower, a C&L 76mm trueflow intake pipe, I am going to buy a cam( don't have a clue yet), some 24# injectors and a set of headers to finish out the exhaust plus the stuff in my sig. My motor has 106K easy miles on it and is very reliable. Is it going to be worth breaking the seal on a reliable motor to do the upgrades that I have listed? I have done a good bit of reading on cobra motors( which is basically what I will have) and the numbers are not making me want to tear my motor down. Who has some experience with this? Don't even care about hearing about alum heads or different intakes, I already have the Ford parts and I'm going with them or nothing at all, I want low dollar power.

red95gtconvert · Sep 5, 2008

Do it, you will make noticable gains from making those mods. I installed GT40P's and an intake off a 94 Cobra and picked up alot power all the way around from it. The car is a fun to drive street car from the upgrades.

final5-0 · Sep 6, 2008

cmozez said:
I have a set of Gt40 heads that I am going to home port, a Cobra intake that I am going to have Tmoss port the lower, a C&L 76mm trueflow intake pipe, I am going to buy a cam( don't have a clue yet), some 24# injectors and a set of headers to finish out the exhaust plus the stuff in my sig. My motor has 106K easy miles on it and is very reliable. Is it going to be worth breaking the seal on a reliable motor to do the upgrades that I have listed? I have done a good bit of reading on cobra motors( which is basically what I will have) and the numbers are not making me want to tear my motor down. Who has some experience with this? Don't even care about hearing about alum heads or different intakes, I already have the Ford parts and I'm going with them or nothing at all, I want low dollar power.

I want low dollar power

the numbers are not making me want to tear my motor down

Don't even care about hearing about alum heads or different intakes

I have done a good bit of reading on cobra motors( which is basically what I will have)

You plant an apple seed and get an apple tree

It seems you are looking to use OEM parts
and
Desire to obtain aftermarket parts results

Believe me ... I understand :Word:
but
If it was that easy ... Everybody would have already done it

In no way am I being critical or trying to put you down

You are wise to ask these Q's before going farther

How much performance do you want?

What are your goals and expectations?

Many here have done the OEM parts thing as well as aftermarket parts

So give us some specific info
and
I'd bet you get some specific replies back

Grady

cmozez · Sep 6, 2008

Grady,
I would love to get some aftermarket heads and hit 300rwhp but the heads I want( AFR) are just to expensive once you figure in all the supporting equipment. I would like to see 260 to the wheels. I don't think that is out of range but I could be wrong. I have read all the stuff about people getting right at 300 to the wheels with the P heads and wonder why that can't be done with the three bar 40's. BUT I am keeping my expectations in check. I just want a fun, peppy street car that I can pile in and drive 800miles and not have any worries. I want to drop about another grand and be done with it.

Hey Red95- thanks for the input, thats what I want, input from guys like you and Grady that have done it, not from knuckleheads like me that have read about it.

final5-0 · Sep 6, 2008

cmozez said:
Grady,
I would love to get some aftermarket heads and hit 300rwhp but the heads I want( AFR) are just to expensive once you figure in all the supporting equipment. I would like to see 260 to the wheels. I don't think that is out of range but I could be wrong. I have read all the stuff about people getting right at 300 to the wheels with the P heads and wonder why that can't be done with the three bar 40's. BUT I am keeping my expectations in check. I just want a fun, peppy street car that I can pile in and drive 800miles and not have any worries. I want to drop about another grand and be done with it.

Hey Red95- thanks for the input, thats what I want, input from guys like you and Grady that have done it, not from knuckleheads like me that have read about it.

Good to be able to talk to you today

I got the time while waiting for software to load ... please wait

In no way would I call you a knucklehead

In fact ... You've got my respect for putting in the research time

I now know you got realistic expectations

I have read all the stuff about people getting right at 300 to the wheels with
the P heads and wonder why that can't be done with the three bar 40's.

I'll only touch on that briefly

those who make 300 or better with OEM stuff are the exception to the rule
and
most of the time ........
their torque curve leaves something to be desired
also
99% of the time ... It ain't 300 SAE

But ... if your focus is only on ... PEAK ... power
it can be and has been done

Here are some iron head combos for you to look at

Note: some are STD dyno calibration and some are done with SAE
Since STD usually yields higher numbers than SAE
All these combos are not apples to apples

Grady

cmozez · Sep 6, 2008

Grady,
Thanks for those numbers. Looking at those makes me think I would not gain alot from a cam change, maybe just some 1.7rr. The second GT40 setup is what I am talking about. That is basically what I am wanting, the torque numbers look great and I take it that oem in the cam slot means a GT cam. That looks like a fun combo

final5-0 · Sep 6, 2008

Yes

O riginal
E quipment
M anufacturer

The parts that came on the Stang from Ford

IMHO ... 1.7 and 1.72 ratio roller rockers are W A Y over rated

Sure ... much easier to install than a cam
but
You gain hardly anything

I mean ... its like between 5 and 10
and
If the truth be told ... its closer to 5 than 10 IMHO

Thats the prob with a lot of those bolt on mods

You end up spending a lot of money
then
You realize ... You really ain't made much power

Reality is ... when you get to 240

You want 260 then 280 then 300 ... yada yada yada

You know ... the real deal is ... Most build around the OEM block

And having said all that ... and ... Staying with NA not PA

Sad thing is if you go to the max with OEM stuff about 260 to 290 SAE
then
Dump all that and go to aftermarket stuff about 290 to 320 SAE

You really don't get much gain for the expense of aftermarket

Again ... You are wise to go into all this with your eyes Wide Open :Word:

OH ... Almost Forgot

When I was talking about torque numbers

I was talking about the shape of the torque curve ... not peak tq numbers

Gotta go for now ... My server has almost loaded everything

Grady

thumper460 · Sep 6, 2008

You are your way to a fun and interesting build!! Porting the GT40s is a good step!! Have a good shop do a final performance valve job to tie it all together ( that alone is worth ponies)

290 HP/ 300 tq is easily done with what you have with just the smallest hyd roller camshaft. and the GT heads and Intake and the rest of your ideas!! I agree with the rocker stuff, keep the 1.7s cause they are there, buy a small camshaft and be done with the rocker arm ratio tricks. Just remember that you will be working with the 1.7 Cobra rockers vs the stock 1.6 , keep that in mind as you are looking at lift on the cams... cool??

You are right on the cost and HP gains with aftermarket heads.. you can do the same ( 290-320 WHP ) on a good STOCK ported Head!! And have a few bucks to spend on other parts.. yes??.... Keep a look out in MM&FF mag, they are doing a build with ported E7s... could be interesting!!

Just me....................................

Thumper

Z06killinSBF · Sep 6, 2008

Sorry to hi jak, but how much can the E7's be milled? What would the final combustion chamber be?

thumper460 · Sep 6, 2008

Ruff for figuring.. .005 off is 1cc
.040 off is then ( ruffly) 8cc's
.040 is the about the most before you have to become creative in getting the intake to mate up. I have done over .100 off ...!!

Just me.........................................

Thumper

PS. CC the chamber first.. as there is a LARGE variable between chambers and heads... cool>>

Z06killinSBF · Sep 6, 2008

thumper460 said:
Ruff for figuring.. .005 off is 1cc
.040 off is then ( ruffly) 8cc's
.040 is the about the most before you have to become creative in getting the intake to mate up. I have done over .100 off ...!!

Just me.........................................

Thumper

PS. CC the chamber first.. as there is a LARGE variable between chambers and heads... cool>>

Hmmm..... what does a normal milling cost? I have E7's (64cc) on my 289 vs. the original 54cc heads. I think I thave talked to you before about working on some heads. That was over 2 years ago though. Weren't you associated with MMJAX?

thumper460 · Sep 6, 2008

Nope on the MMjax.. I might have posted there, but never anything else!!
Usually to surface a set of heads flat ( here in Jax Fl) your at 40-60.00 to "Mill" a set usually 20-30.00 more.. just a thought.

Just me.......................................

Thumper

SVTtripleblack · Sep 8, 2008

300 rwhp is possible if you get a really good port job on your heads and intake and have the right supporting mods. Like Grady said however, your torque curve may not be as desireable with the stock iron heads. You can check out my sig if it's any help to you. I'm making 265hp and 306tq at the wheels with untouched heads and intake. I wish I had a better torque curve though, and more punch up high in the rpm range.

I agree that AFR heads are really pricy, but you get what you pay for. They are a darn good head. You might want to consider selling the iron heads and picking up a used set of Edelbrock Performers. That's the route I'm probably going to take.

1995greenstang · Sep 8, 2008

cmozez said:
Grady,
I would love to get some aftermarket heads and hit 300rwhp but the heads I want( AFR) are just to expensive once you figure in all the supporting equipment. I would like to see 260 to the wheels. I don't think that is out of range but I could be wrong. I have read all the stuff about people getting right at 300 to the wheels with the P heads and wonder why that can't be done with the three bar 40's. BUT I am keeping my expectations in check. I just want a fun, peppy street car that I can pile in and drive 800miles and not have any worries. I want to drop about another grand and be done with it.

Hey Red95- thanks for the input, thats what I want, input from guys like you and Grady that have done it, not from knuckleheads like me that have read about it.

with the swap you will easily be at 300 horsepower i have just the p heads with stock intake the heads are ported and without a doubt i am putting atleast 275 to the rear wheels

cmozez · Sep 8, 2008

Thanks guys. This is why I love this site

94greenvert · Sep 11, 2008

I'm running the setup you are talking about and love it. I am through with engine and suspension. I am working on interior and exterior looks. If you have any questions, I'd be glad to answer

cmozez · Sep 13, 2008

Thanks Greenvert,
I will be posting on this more in the winter. I am gathering info and parts right now. I am working on my master electrician liscense right now so I don't have time for the actual work.

Gt40 heads and Cobra intake

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