Cobra Gt 40s

Stanger76 · Oct 27, 2016

Hi all, I have a question about my setup. I have a 91 with 2000 miles on the new bottom end that is a forged 306. I currently have stock e7 heads, b303 cam, 1.6 rr, cobra upper and lower intake, CAI with Bassani headers and Bassani mufflers with no cats or smog. It is a manual with stock rear end. The car has really good torque and runs really well. What I would like to know is about what it's putting out HP and what would the gains be roughly with a set of GT 40 iron heads. Thanks in advanced

Stanger76 · Oct 27, 2016

I have thought about maybe having my stock heads ported but not sure if that would be much of a benefit

General karthief · Oct 27, 2016

Here is what I've gathered from hang'n round here for awhile.
If you are on a budget and you already have the gt40's you will need to do a valve spring udate. They are a good update but keep in mind they are 'old school'. The stock heads are good for a stock motor, thats about all. Better heads are on the market now and they are bolt-n-go. Aluminum if you can, they are inexpensive and light weight, technology has advanced since the gt40 days.
What are your plans for the car? Street/strip or just looking to embarrass an import or two?
Think about a good gear in the back, say 355 or more depending on use.

deathb4dismount · Oct 27, 2016

Stanger76 said:
Hi all, I have a question about my setup. I have a 91 with 2000 miles on the new bottom end that is a forged 306. I currently have stock e7 heads, b303 cam, 1.6 rr, cobra upper and lower intake, CAI with Bassani headers and Bassani mufflers with no cats or smog. It is a manual with stock rear end. The car has really good torque and runs really well. What I would like to know is about what it's putting out HP and what would the gains be roughly with a set of GT 40 iron heads. Thanks in advanced

215ish at the tire

Black1987 · Oct 27, 2016

deathb4dismount said:
215ish at the tire

^^This

However with a better cam, larger TB, maybe some 24s (not necessary) and bumped timing = 250-260ish with an auto 260-270ish with a manual

Stanger76 · Oct 27, 2016

It's only a street car that's driven occasionally. What would be a good aluminum head that would really add to the combo it already has that would be a direct bolt on and about what would it add? I don't have the gt40s yet it was just a thought. What about gt40x heads?

Stanger76 · Oct 27, 2016

It has a 75mm throttle body now. So basically u r saying about 215 which is what bone stock they put down isn't it? So the combo it has it I guess pretty much bone stock that I have

deathb4dismount · Oct 27, 2016

Stanger76 said:
It has a 75mm throttle body now. So basically u r saying about 215 which is what bone stock they put down isn't it? So the combo it has it I guess pretty much bone stock that I have

yes. 215ish at the tire, stock makes 215ish at the crank, not tire.

FoxMustangLvr · Oct 27, 2016

Stanger76 said:
It has a 75mm throttle body now. So basically u r saying about 215 which is what bone stock they put down isn't it? So the combo it has it I guess pretty much bone stock that I have

They are guessing 215hp at the rear wheels (aka rwhp.....rear wheel horse power). This estimate is after power train losses.

a91what · Oct 27, 2016

For the money I would buy nothing less than trick flow 170cc heads... it'll be money very well spent

Stanger76 · Oct 27, 2016

Gotcha I thought he/they was saying 215 flywheel. one of my builders have a 93 cobra thats really nice and sounds good but I roasted him so when I read that I was thinking does his cobra only make about 190 to the flywheel.. I'm not really sure what else has been done to mine. The guy that owned Dugan racing in Duluth GA was originally building the one I have for a turbo for track use and my girl bought it from him for a birthday gift for me ""good woman" after my 07 was totaled by a drunk driver. I do know the 91 feels much stronger then my 07 did but it was a auto also but hack on topic would a set of gt40x be a good direct bolt up?

Stanger76 · Oct 27, 2016

Would the trick flows be a direct bolt up

RangerJoe · Oct 27, 2016

TFS 170's or AFR 165's.

Joe

RangerJoe · Oct 27, 2016

Heck, depending on the pistons, I would go AFR 185''s if the valve notch is big enough.

Joe

Stanger76 · Oct 27, 2016

It also has electric fan and underdrive pulleys upgraded alternator and 125 shot of nos.

deathb4dismount · Oct 27, 2016

Stanger76 said:
Gotcha I thought he/they was saying 215 flywheel. one of my builders have a 93 cobra thats really nice and sounds good but I roasted him so when I read that I was thinking does his cobra only make about 190 to the flywheel.. I'm not really sure what else has been done to mine. The guy that owned Dugan racing in Duluth GA was originally building the one I have for a turbo for track use and my girl bought it from him for a birthday gift for me ""good woman" after my 07 was totaled by a drunk driver. I do know the 91 feels much stronger then my 07 did but it was a auto also but hack on topic would a set of gt40x be a good direct bolt up?

The cobra probably makes more power. TFS heads will bolt up. What's your budget?

Stanger76 · Oct 27, 2016

Don't really have a budget but was trying to keep it around 1000

deathb4dismount · Oct 27, 2016

Stanger76 said:
It also has electric fan and underdrive pulleys upgraded alternator and 125 shot of nos.

oh now it has

Stanger76 · Oct 27, 2016

Yes but no spray used when racing the cobra. I don't like spraying it

cleanLX · Oct 27, 2016

Mine, with totally stock long lock made 232 with 76mm MAM and long tubes off road H and 2.5 cat back... stock intakes/cam/TB/heads etc etc.
With a fresh 306 and the mods you listed I would expect wheel hp up over 230, because, most low mileage cars back in the day were over 230 at the tire. 240 was not uncommon.
In theory, a stock (as cast) set of GT40 irons "should" give you another 30. 260-270 seems to be the norm with that type of combo on a fresh bottom end... although having said that it's important to address the fuel pump and injectors to get there.
Pretty much any of the popular heads will "bolt on", but with any set, you are still looking at checking push rod length and PTV clearance because, anomalies.
Heads... it comes down to budget and desires.
You can make 350+hp to the wheels with Ford iron heads, but it will be a tonne (spelled in metric, because it's more) in $ over what a typical simple aluminum head setup will run you and drive-abilty may be on the poor side for your desires.
A typical aluminum head setup is going to make 280-300 given all the support items are there (fuel exhaust).
Getting over 300 at the wheels starts to become more involved, porting of heads and intakes, valve jobs, well matched cam/valve train.

So, bolt on some GT40 irons, possibly as much as 30hp more than the stock E7's.
You are sure the E7's are stock/unmodified right? Because if the guys at Dugan Racing worked those E7's over, it's possible a set of GT40 irons will net you very little, and, possibly even take you backwards.

Cobra Gt 40s

Stanger76

Stanger76

General karthief

wonder how much it would cost to ship you a pair

deathb4dismount

Crap, didn’t realize my crotch was in that picture

Black1987

my wife Bedazzled my input shaft

Stanger76

Stanger76

deathb4dismount

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FoxMustangLvr

I love my Pimp

a91what

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Stanger76

Stanger76

RangerJoe

I leave the horn on while driving

RangerJoe

I leave the horn on while driving

Stanger76

deathb4dismount

Crap, didn’t realize my crotch was in that picture

Stanger76

deathb4dismount

Crap, didn’t realize my crotch was in that picture

Stanger76

cleanLX

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