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if the funds are available then go for it... there is a poster around here dont remeber his name...but he has Stage 3 Ported GT-40'S with a S-Trim i think and is making over 500HP to the wheels...so they can flow.
Anything can make Hp if you boost or spray it. With his same setup and some good heads he probably would have made 600+
 

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Why do you need to look stock? Unless you're getting the motor inspected for a class event why do you care so much? Hell you can always paint a set of aluminums black and look stock with them too.

I just think its a total waste of money and it WAS in my personal experience.

But hey its your money, if you want to spend $1000 on a set of iron heads that can't grow any more later on down the road more power to you.
If he plainly said he was not worried about cost, he's probably doing it so that he can have a measure of satisfaction of having a very good running car with heads that no one else wouldn't want to put any money into. Read his sig......
 

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I would have to assume the OP has a 94-95 cobra and wants performance with a stock look.I would say a nice ported set of GT40's,ported intake,roller rockers,cam and gears would be an easy 12 second car with a tire and real fun on the street for less money then a TFS top end kit.
Theres nothing wrong or stupid about this approach.You can't tell me walking up to a mustang/fox which just ran a 12.50 and it looks like an untouched engine ain't cool?
 

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I would have to assume the OP has a 94-95 cobra and wants performance with a stock look.I would say a nice ported set of GT40's,ported intake,roller rockers,cam and gears would be an easy 12 second car with a tire and real fun on the street for less money then a TFS top end kit.
Theres nothing wrong or stupid about this approach.You can't tell me walking up to a mustang/fox which just ran a 12.50 and it looks like an untouched engine ain't cool?
especially if it just laid the smack down on an aluminum headed car !!
 

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if the funds are available then go for it... there is a poster around here dont remeber his name...but he has Stage 3 Ported GT-40'S with a S-Trim i think and is making over 500HP to the wheels...so they can flow.
WTF is "stage 3 ported"???

Damn ricers and their videogame language really piss me off.


If you port heads, you measure their flow with a flowbench. There is none of this "stages" bull####. This isn't Need For Speed or Gran Turismo!
 

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stock untouched gt-40 irons can make some nice power with a little boost that is.... 505rwhp to be exact!
 

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Discussion Starter #27
I appreciate the comments of support.

To those that PM'd me with some great leads thank you.

I know this Iron head has it's limits. Every head does. The question is still simple: Who out there is reaching the limit of a GT40 Iron head and what is that limit.

There are a lot of people that have enjoyed great performance out of ported E7's The only reason GT40's were not exploited to the same level was the onslaught of after-market heads.

I'll still welcome recommendations and flow numbers from someone that has a great set of GT40's or knows someone that can produce a great set.
 

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I'll still welcome recommendations and flow numbers from someone that has a great set of GT40's or knows someone that can produce a great set.
Go over to the hardcore5.0 site, and pm Outlaw5.0, and ask him, think he had some experience with them. Couldnt dig up the flow numbers I saw awhile back, but they were impressive.

btw, many still appreciate doing more with less, thats what makes it fun, and a challenge.
 

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You'd be wrong. By the time you buy new valves, springs and get them ported you'll be into them at LEAST $800(more likely over a grand) and there are LOTS of used Edels and TFS heads in great shape that you can get for that price or less on the classifieds here.

Ask me how I know.
OR, you can do like I did a few years ago and buy some used Alum's, eddy's in my case, that cost 750 and needed new guides, valves and springs and have more in them than what they cost NIB. IMHO, used is a bad idea unless you can actually look at them in person, Iron or aluminum. Just fair warning if you buy online.


For GT40 heads you grind the egr bumps off and MAYBE get them milled. Thats it.
Maybe? No, You do. Huge chambers there my man. You DO get them milled. Im not disagreeing with your opinion on the complete matter, as soon as I tear this motor up, Ill be doing another set of alum's. I just felt it necessary to make that milling part known. Theres no maybe about that at all.



For me and my 40s, the breakdown is
Heads: $100
Rev Valves: $135
TFS Springs: $125
Machine work; VJ, guides, milling, hot tank, all the porting, assembly: would have been $500. However, I worked there, so I did it all after hours with a little help. Obviously, this plays a huge role in why I chose to use these heads. I had practically nothing in them.
 

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This is my understanding.. XSR supposedly has a great program for GT-40's again, supposedly, puts them near 165 afr's both intake & ex.

If it's true, not going to be cheap though.. your still going to be better off with AL's for the thick deck and modern chambers..

http://www.xsrcylinderheads.com/home
 

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What about starting with some Windsor Sr.'s or Windsor Jr's? I've seen some great #'s out of both when ported. Out of the box the Jr's will keep the tq of unported GT40's and out flow them in the higher lift ranges. I notice them going for somewhere in the $450-$600 range. Sr's in the $600-$750 range.
 

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Looking for a head porter with a very good CNC program for these heads. Who did you use? What were the final flow numbers? what did it cost?

Thanks
I did a self port in the garage with miscellaneous hand tools and a dremel. Haven't had a chance to bench test them yet, but I'll let you know when I get some numbers.
 

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Discussion Starter #33
Go over to the hardcore5.0 site, and pm Outlaw5.0, and ask him, think he had some experience with them. Couldnt dig up the flow numbers I saw awhile back, but they were impressive.

btw, many still appreciate doing more with less, thats what makes it fun, and a challenge.
Thanks for all the leads. I have a number of them to run down.

If anyone come up with another source please PM me.
 

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Does anyone make a nice set of direct replacement stainless valves for the P head? How much for a set of intake and exhaust valves and what size are they?
 

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Buy my REV stainless 1.94/1.6 valves. Never used them and they checked out fine at my machine shop. You'd have to get a little portwork done though.
 

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You'd be wrong. For GT40 heads you grind the egr bumps off and MAYBE get them milled. Thats it.
Sorry to thread hijack, hoping someone can address this....Any pics here or elsewhere of the egr bumps? I've got a GT40's on my Lightning engine, and would like to clean them up. These GT40's also have the Thermactor holes drilled in the rear, I believe the Explorer GT40's do not. Any value in starting with non Thermactor drilled heads vs. the ones I have?

What is a safe amount to mill off? I'm assuming this is to bump compression? Since I'm probably going to a TFS1 cam, the bump in compression will help with the GT40's I have.
 

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Sorry to thread hijack, hoping someone can address this....Any pics here or elsewhere of the egr bumps? I've got a GT40's on my Lightning engine, and would like to clean them up. These GT40's also have the Thermactor holes drilled in the rear, I believe the Explorer GT40's do not. Any value in starting with non Thermactor drilled heads vs. the ones I have?

What is a safe amount to mill off? I'm assuming this is to bump compression? Since I'm probably going to a TFS1 cam, the bump in compression will help with the GT40's I have.


just look in the exhaust port. there will be a little cup looking spot in there. thats the bump. just behind it, you grind that off till you have a fairly smooth transition. No difference in starting with either. They are the same. Youll just have to plug the stuff on yours.

Milling .030 is the typical number. Since the chambers can vary 64-67 its best to cc them and figure out how much to mill. 60-61 is the number to shoot for cc size. I think that took a .035 cut on mine. Lightnings I think were around the same and Cobras were a little less, "factory milled". As for compression bump, some guys have to mill the 40s just to get back to stock CR. So its not necessarily for a bump above. The P Heads are where you start bumping the CR.
 
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