I was wondering if anybody knows the difference in exaust port between the g500 heads and our heads. Are the ports raised or lowered or is it just a different style flange? Can headers that fit our cars be modified to work with gt 500 heads?
GT 500 heads
- Thread starter 32vApe
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the heads are significantly reshaped from our heads. Stock 99-01 headers will bolt up, but cause a port mismatch/flow restriction. If you don't want to go long tubes, a set of terminator stock logs would be a better choice.
GT500 heads will not be a good choice for a 281ci motor. Also, there is only one intake that will fit a 4.6 block with GT heads and that is the FR500C intake. It's available from Ford for about $2200.
Yea, you'd be better off just getting some '03+ DOHC heads and getting them worked over by whomever you choose.
The FGT heads are completely diferent approach and intake or headers will not fit. The header bolt pattern is completely diferent so you have to go custom.
As Todd stated, the only available intake is the FR00C = ~2200 bones
I have been doing my own custom sheet metal, have spent lots of time doing the right calcutation for Plenum, and runner lenghts.
The heads on a 28XCIs will be too much. As a minimum a Big Bore and a BB/Stroker will be the best.
Naz
As Todd stated, the only available intake is the FR00C = ~2200 bones
I have been doing my own custom sheet metal, have spent lots of time doing the right calcutation for Plenum, and runner lenghts.
The heads on a 28XCIs will be too much. As a minimum a Big Bore and a BB/Stroker will be the best.
Naz
The plan for next winter is an all motor bb/stroker. Just trying to plan out the setup in advance. I want to get some stepped Kooks headers soon and if I go with fgt heads and an fr500c intake I was just wondering if those headers could be modified to fit the fgt heads. I have a TIG welder and can modify them if it is close or the flanges just need to be cut off and changed. The goal is at least 500whp so I want the best flowing heads possible. The car will also be used for open track road racing and I understand that the cooling is better with the fgt heads over the 03-04 castings. One more question though, If I do go with 03-04 castings I would probably run a sullivan, I know naz ran one with good success. Does it give up and torque in the midrange(4k-5k) due to the short runners over a sheet metal. I dont mind spending $2000 on an intake but if the sullvan works well I would run it.
The Sullivan on the BB/STR was equal to the FR500 intake up to ~3800-4000RPMs, from there it completely out powered/out TQ'd the FR00 intake with instant, and I mean, explosive trottle response and pulled like a freight train!
Sending you a PM right now.
Naz
You could modify the headers as long as the port spacing is the same.
The FR500C intake will keep peak power at a relatively low rpm due it's longer runners. So, if you want to keep your BB/Stroker's peak power at a relatively low rpm the FR500c intake will work and it should provide great midrange and lower rpm power also. With that, you will be hard pressed to get 500rwhp with an FR500C intake.
The FR500C intake will keep peak power at a relatively low rpm due it's longer runners. So, if you want to keep your BB/Stroker's peak power at a relatively low rpm the FR500c intake will work and it should provide great midrange and lower rpm power also. With that, you will be hard pressed to get 500rwhp with an FR500C intake.
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There is a mod that corrects this by running a coolant passage hose behind the heads connecting them.
n/a combinations don't have any cooling issues with the newer, revised casting 04 heads that you would get from most of the people that sell ported, new casting heads.
BTW, you can modify the Sullivan to fit the GT heads...it's been done.
Yeah, 100% agree. The reason why I walked away from the FR500C intake.
The port spacing is diferent on the FGT heads and it will require a new flange as well as cutting the primary tubes about 8 inches down from the flange and bent your own tubing, etc. And you must ensure that you dont hurt the exhaust port flow of the FGT head. The turn radius on some of the primary tubes could be easily compromised when modifiying the header.
Bottom line: The headers will cost you $$$
The intake options are FR500c or custom (Huge $$$$) or fab your own as I do:
Check out the PM I sent you.
Naz
Yes, but on 5.4 Based block. That set up does not alters (SP?) deck height of the intake flanges so what requires is matching of the 5.4 Sullivan intake ports which are very close to the 2.370" of the FGT Port and requires extensive modificaitons.
The port on the C-headed Sullivan is way smaller than that, and he 5.4 based will be completely off.
Naz
Isn't the deck height of the GT intake flanges the same as all other 4v heads?
Ah, I thought the fr500c intake would make peak around 7200. I thought I read somewere that the airhorns are removable and you can put longer or shorter ones to tune for rpm range. If thats not the case, Then maybe I will stick with 04' castings. I figured it would need to peak at least there to make 500whp. I really want to fab my own intake, but I do not have enough tools (shear,brake,band saw) to work aluminium. I can weld it but thats about it. Naz, if you make one that works well and wanted to make another one next winter I would be in the market for one. I also talked to a guy from Logan. They make sheet metal intakes for 4v, but for $2500. Thaks for all the replies guys.
subbing for cool tech info 
So, what would be the difference in peak RPM from FR500 to Sully? It sounds like I should sell the FR500 for the Sully to fund the bb/stroker build when the time comes. Cam selection effects this of course.
The Sullivan will out power the FR500 in the top end.
On the mid range on the 322 and the FR500 should be very interesting.
I can only ref to my BB/FR500 combo vs. my old 322, Sullivan combo which is really no fair compare of the two.
Naz
I'm not sure about that Carlos. We did a same day dyno on a very high hp/high revving n/a engine and the Sullivan made only a couple more hp throughout the entire range and hp dropped off at the same rate after peak. Peak HP occured at the same rpm and graphs followed exactly the same curve.
yup, get it wrong and all bets are off.
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Got it, understand.
We are planning on doing a back to back dyno testing of, hope to do very soon:
FR500 vs Sullivan vs Nazty Ported Short Runner
More to come.
Naz
Yea, sorry about that. I should have let you hang on to that intake so you could have done that. I didn't even install it for another 8 months :nonono: I think the comparison could be very useful to this forum. Do it with your bb/stroker and my stock shortblock.
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