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Topic: GT-40 Intakes and Heads Questions
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norcalfiddy
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Member # 11207
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posted
ok, so are all GT40 heads the same? ive heard of non P's, P's, and 3 bar. what all does that mean?
and for the intakes, are they all the same? ive heard of tubular, explorer, and cobra.
help me out! looking to get gt40 heads and intake on my fox and what to know what to get, thanks!
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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JON_SVT
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Member # 9621
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posted
The gt40 heads have 3 bars on the side. The gt40p heads have 4 bars on the side. The gt40p heads require special headers due to the spark plug angle. The intakes are different. You can tell them aprat real easy
Posts: 2608 | Registered: Nov 2009
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by 65coupe87notch: The gt40 heads have 3 bars on the side. The gt40p heads have 4 bars on the side. The gt40p heads require special headers due to the spark plug angle. The intakes are different. You can tell them aprat real easy
ok cool.
but are the ports and valves all the same on the heads?
and same with the intakes, all the same internally? i know they look different on the outside
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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Duncan Motors
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Member # 7045
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posted
all the intakes flow almost the same. the p heads i think have a better angle plug, but interferes with headers unless u buy the right ones, and i think one 0f them actually have a tad bigger valve as well.
Posts: 6310 | From: Vallejo | Registered: Sep 2006
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Sydewayz_Stan
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Member # 10217
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posted
the difference is the gt40's have 1.84/1.54 valves and it has the thermactor passages so you can run all the stock smog equipment without modification. the gt40p's have 1.84/1.46 valves but flow better because they have a better combustion chamber design (thats why the spark plugs are at a different angle) and they dont have thermactor passages (humps) so it flows better on the exhaust side. but you wont be able to hook up all the smog stuff properly and you have to get special headers to clear the spark plugs
-------------------- -90 Vert-SOLD -91 Notch-SOLD -2000 Explorer 5.0-SOLD -72 Maverick-SOLD -2004 GT, vortech V2 si, 10 psi- -2002 F150 supercrew-
Posts: 3432 | From: 707 vallejo/richmond 510 | Registered: Aug 2010
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by sydewayzLX50: the difference is the gt40's have 1.84/1.54 valves and it has the thermactor passages so you can run all the stock smog equipment without modification. the gt40p's have 1.84/1.46 valves but flow better because they have a better combustion chamber design (thats why the spark plugs are at a different angle) and they dont have thermactor passages (humps) so it flows better on the exhaust side. but you wont be able to hook up all the smog stuff properly and you have to get special headers to clear the spark plugs
thanks, so do the regular gt40's show a improvement over the stock e7's? is it worth doing? or show i just port the stock heads?
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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Sydewayz_Stan
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Member # 10217
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Id say with gt40 heads and intake you should see about 15-30 hp depending on the cam and other supporting mods. Personally i would spend an extra 500-1000 and double your gain by getting some quality aluminum heads and aftermarket intake.
-------------------- -90 Vert-SOLD -91 Notch-SOLD -2000 Explorer 5.0-SOLD -72 Maverick-SOLD -2004 GT, vortech V2 si, 10 psi- -2002 F150 supercrew-
Posts: 3432 | From: 707 vallejo/richmond 510 | Registered: Aug 2010
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85staNg302
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Member # 9450
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Like u said u can also port the e7s ..I run mid 12s on ported e7s
Posts: 1561 | From: sacramento | Registered: Sep 2009
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norcalfiddy
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Member # 11207
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quote: Originally posted by 85staNg302: Like u said u can also port the e7s ..I run mid 12s on ported e7s
really? what cam are you running? what intake manifold?
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by sydewayzLX50: Id say with gt40 heads and intake you should see about 15-30 hp depending on the cam and other supporting mods. Personally i would spend an extra 500-1000 and double your gain by getting some quality aluminum heads and aftermarket intake.
ok thanks.
im doing this on a budget and i already have a cam, so i might go with gt40 intake and ported heads or gt40 heads.
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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wilit
Mustang Messiah
Member # 3367
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There are two GT40 (3 bar) castings. The GT40's that came on Cobras and Explorers have 7/16" head bolt holes and 61cc chambers. The GT40's that came on lightnings have 1/2" head bolt holes and 64-65cc chambers.
-------------------- "If a man hasn't found something worth dying for, he isn't fit to live." - Martin Luther King Jr.
Posts: 4793 | From: 37.78514° North 122.40100° West | Registered: Oct 2003
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MACK.GT
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Member # 10461
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Do it to it , ITS WORTH IT
Posts: 446 | From: 510 | Registered: Nov 2010
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85staNg302
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Member # 9450
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quote: Originally posted by norcalfiddy: quote: Originally posted by 85staNg302: Like u said u can also port the e7s ..I run mid 12s on ported e7s
really? what cam are you running? what intake manifold?
Stock cam..rpm proformer with a shitty ass carb
Posts: 1561 | From: sacramento | Registered: Sep 2009
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84SVOrick
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Member # 9039
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quote: Originally posted by sydewayzLX50: Id say with gt40 heads and intake you should see about 15-30 hp depending on the cam and other supporting mods. Personally i would spend an extra 500-1000 and double your gain by getting some quality aluminum heads and aftermarket intake.
the only thing i disagree with is the EXTRA $500-$1000 hahahaha, i got a very generious power increase using gt40 heads, tfs1 cam, and typhoon intake haha, paid a lot less then i would of on sum used alum heads. but if you got deep pockets you could get sum nice alum heads with 2.02 valves and much bigger c.c.'s
-------------------- Bay Area Stunnaz RIP Jeannera "FOXY302" 10/29/87-10/9/10 1984 SVO 302 HCI a basic bitch 1986 GT FOXY302 stolen and totaled R.I.P.
Posts: 1928 | From: Vallejo CA | Registered: Mar 2009
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1FAST89GT
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Member # 5071
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Gt-40 heads with 1.7 rr , intake, throttle body , mass air, injectors, fpr and some gears. Good little runner right there
Posts: 4915 | From: VALLEJO | Registered: May 2004
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LXjames
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Member # 10791
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Cody the intake I showed you I have is off an explorer there's a cobra upper an lower on Craig's for 200. Get some already ported gt40's non p's and keep your cam and you'll be set.
-------------------- On Point Motorsport prez. King Lx
Posts: 4761 | From: Pittsburg CA | Registered: Mar 2011
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racsirx
CAFords OG
Member # 1710
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posted
GT40 heads are good heads, just depends on what you wanting out of your setup. There is a member on here running 11s with not ported stock e7 heads, not ported stock intake, and custom stock spec cam with some duration. I made 400hp with a 306, 9:1 compression, stock cam, cobra intake, acid dipped gt40p heads(which is illegal for the class my Coupe was in) and ran a best of 12.2xs with a lentech AOD and 4:30 gears. But I agree some aluminum heads would give you more benefits, especially if you are planning to put a blower or a turbo at a later date.
-------------------- 88 Saleen #564 88 GT 331 NOVI2000 88 Coupe TURBO 9.75@142 95 Cobra R #75-SOLD 06 F250 13 BMW AH3 17 GT350 #5556 GOD'S NOT DEAD
Posts: 20750 | From: Concord & Pittsburg, CA | Registered: Aug 2002
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by LXjames: Cody the intake I showed you I have is off an explorer there's a cobra upper an lower on Craig's for 200. Get some already ported gt40's non p's and keep your cam and you'll be set.
yea i know. thats probaly what im goin to try to pickup. and i wanna get some heads but i think im just gunna wait and get some real heads. but idk yet.
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by racsirx: GT40 heads are good heads, just depends on what you wanting out of your setup. There is a member on here running 11s with not ported stock e7 heads, not ported stock intake, and custom stock spec cam with some duration. I made 400hp with a 306, 9:1 compression, stock cam, cobra intake, acid dipped gt40p heads(which is illegal for the class my Coupe was in) and ran a best of 12.2xs with a lentech AOD and 4:30 gears. But I agree some aluminum heads would give you more benefits, especially if you are planning to put a blower or a turbo at a later date.
hmm, i would just keep my heads but everybody is saying that my cam will make it have less HP. ive been looking at gt40's but seems like im better off just saving up and getting some aluminum heads.
and i do plan on going turbo'd hear soon, mostlikely before i do heads. its all just a matter of getting $$ to do it. lol thanks lee
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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racsirx
CAFords OG
Member # 1710
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posted
Leave it stock and put the turbo, you can easily get 450hp with a 70mm turbo that way. But if you want to install a cam with a turbo put a F303. Don't forget to install a MSD two step so you can make boost out of the hole, otherwise you will hate your 60ft time. After 500hp or more than 12lbs of boost with any of the iron heads you will have a great risk of blowing a head gasket.
-------------------- 88 Saleen #564 88 GT 331 NOVI2000 88 Coupe TURBO 9.75@142 95 Cobra R #75-SOLD 06 F250 13 BMW AH3 17 GT350 #5556 GOD'S NOT DEAD
Posts: 20750 | From: Concord & Pittsburg, CA | Registered: Aug 2002
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norcalfiddy
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Member # 11207
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posted
quote: Originally posted by racsirx: Leave it stock and put the turbo, you can easily get 450hp with a 70mm turbo that way. But if you want to install a cam with a turbo put a F303. Don't forget to install a MSD two step so you can make boost out of the hole, otherwise you will hate your 60ft time. After 500hp or more than 12lbs of boost with any of the iron heads you will have a great risk of blowing a head gasket.
really? i think i might just do that. i think i seen some build on a stock 5.0 and they threw a 70mm on and it made i think 422hp or something to the wheels. would i see less hp with a e303 over a stock cam? and how much psi of boost can i safely run to make the motor last for a while? but yea i think im just gunna get a turbo kit and forget the heads for now.
what you think about the on3 performance kit they sell? good starter kit? pros and cons.
thanks, cody. [ December 27, 2011, 08:02 PM: Message edited by: norcalfiddy ]
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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