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I had a set that were CNC ported by Fox Lake.the program barely touched any ofh the intake runner,just the gasket match and a slight amount in the bowl.it was a complete CNC port on the exhaus though.i ended up doing a decent amouint to the intake runner and bowls and a little more to the exhaust port.

i always loved the look on peaples faces when i put a whooping on them with a iron headed setup.

btw it ran high 11's at 115mph as my daily driver.
 

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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.
Awesome....Thanks for the pointers. :salute:
 

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I have a 90lx with ported and milled cast gt40 heads and portmatched gt40 intaked with a custom cam and made 320rwhp and my and my buddy has aluminum heads makes same power
 

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I guess my only gripe with the iron heads is the weight and they leave you no room to grow as I've stated. HOWEVER if you must do them and you want to spank someone with as stock looking engine then w/e.

As I also said before there are plenty of good porters. Thumper is one that comes to mind right off the bat. Do some searches on here and you'll get info on a bunch more. If you're anywhere near Northern New Jersey I know of a really good porter that'll do a kick ass job on your heads. He doesn't do shipped stuff though(doesn't take credit cards...)

Just make sure you do the custom cam too.
 

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I have pulled over 400 hp at 6000 rpm with ported DOOE heads on a 302. This was with a 220 duration cam at .050 and .500 lift. Weight savings in my book isnt a big deal general rule is for each 8 pounds removed you gain the equivilant of aprox 1 HP. With biger port aftermarket heads the loss in low end power vs the small gain in peak power dosent compisate for the losses in llow end. There are cases such as running road course events were the weight saving might improve handling aluminum might be an advantage or a bigger engine like a 351 or more needs a larger port.
 

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You may want to do a search on here for GT40/P heads...there were many post about them a few years ago. For some examples of what unported gt40 heads can do..look at NHRA stock class (low 11's n/a) and nmra f/s (11.4's at 119 on dr's this season). I have a been there/done that experience. Back in '01 I had Neil Erickson at MIT prep a set of P heads for me. I sent him a bare set of p heads. He hand ported them and my gt40 lower intake. I used REV 1.84/1.54 valves and comp valvesprings/retainers/locks. Neil did great work at a very reasonable price for me. But still I probably had $800+ in that set of heads. That combo was a stock shortblock, ported p heads, gt40 intake w/ ported lower, mild HR custom cam (.513" lift, 223 dur., 113 lobe sep), 30# inj.,65mm t/b, 76mm mas, 1 5/8"lt, 2 1/2" dumped exhaust, 3550, 4.30 gears, 28x9" slicks at the track, used a FMS extender to bypass the stock rev limiter on the spray. It went a best N/A of 12.19 at 110 w/ ~1.55 60', 200 shot (NOS efi gt40 plate kit) 10.98 at 126 w/ only a 1.65 60' @~3200#. On a chassie dyno it put down 296/322 to the wheels n/a. I had pretty good results that I was happy with from that combo. But looking back I know I could have probably done better (performance and $$ wise) if I just started with a used set of AL heads.
 

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For me it broke down like this:

Stock 1.84IN 1.54EX valves, 5 angle valve job
new springs, $60 (designed to work with E303 cam)
Port job (intake ports and bowls worked over, exhaust cleaned up, nothing outrageous)
Milled heads to true them, .003" and .005" respectively (no milling done to increase compression)
Cost of heads, $325 complete (1998 Explorer heads)
Stock valveguides were within specification, and I'm using pedestal mount rocker arms, so saved money there.
Cost of all the machineshop work was $665 on the heads, I had him port match an explorer intake too, $150 for that.

I have $990 in my GT40 heads. That's about the limit of what you should put in them, I think. New aluminum heads start about that price, flow better, and weigh less for the price.
Great!! I believe he asked where? Not what you had done and what it cost?
 

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Well, not for nothing I understand its a very old thread yet I never saw this thread when I searched here for GT40 heads. So in a way, this time it benefitted. Found a little more information on these GT40 heads.
 

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Well, not for nothing I understand its a very old thread yet I never saw this thread when I searched here for GT40 heads. So in a way, this time it benefitted. Found a little more information on these GT40 heads.
Yeah, GT40 heads suck.

E7's and GT40's flow under 200cfm, ported you may see near 225cfm or so, wow. Aftermarket low end heads should all flow over that, and 250cfm is kind of common now. Costs have gone up no doubt, but the popular heads are closer to 275cfm these days. Those are all light years past the old ported GT40 stuff.

...I pulled the sarcasm.
 

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Dude all I was saying is this time a dead thread brought to light was good. I learned more, seeing I wasn't able to find this thread in a search. I use to question on bringing old threads back to light or even side with deleting them, now I'm seeing it might MIGHT help someone.
 

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Dude all I was saying is this time a dead thread brought to light was good. I learned more, seeing I wasn't able to find this thread in a search. I use to question on bringing old threads back to light or even side with deleting them, now I'm seeing it might MIGHT help someone.
I'm not disagreeing with you, many old threads are valuable. The OEM Ford SBF head threads are very common still, most of them should explain basically what this one does early on. I just used more specific data points, CFM levels, to say the same thing. The old OEM heads are cheap when you find them, but after rebuilding them properly, the cost is more than the results.

I've hunted used TFS heads many times, those you have to be patient to get, but in the end the performance is well worth the costs.
 

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Oh god I saw this in my subs... Some dude likely with a small pecker felt the need to res a 12yr old thread to try to act like a tough guy online. Well done.

As for the GT40s, I've had a lot happen and learned a lot about these platforms in 12 years. Even back when this thread was made GT40s were not worth it and now they really aren't unless you happen to find a real low mileage exploder engine out of a yard and are just looking for a cheap power bump to a 95-down car. Or if you happen to own a 93-95 Cobra with an engine that hasn't been messed with. On those cars if you want more power you just get a S trim and do the exhaust and suspension. That's it. Will make enough power to split the stock block so keep the power down around 425whp. It'll drive like stock off boost and being a pushrod it'll have a lot more grunt than a modular. I would still take a modular tho. Just a better engine and a lot more tunable.
 
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