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Hi guys,
I was debating swapping my 98 heads with a set of 99+PI heads. I was shopping around and it seemed to be more of a headache. I mean getting a new intake and some other misc. parts and not to mention the labor involved installing this set up. I was in the process of purchasing a set but I went to livernoismotorsports.com and a gentleman by the name of Rick Swain (real cool guy by the way) claims that he can make the 96-98 heads flow better and produce more power than a stock and modified 99 PI head . He faxed me a comparison flow sheet and it looks very promising. He is in the process of testing a stock 98 mustang gt with the 99pi heads, the FMS 96-98 replacement heads and of course Mr. Rick Swain's 96-98 heads w/ PI cams as well as livernois cams. If he is successful (which I have a feeling he will) this will make the 99pi head swap history. This will be considered a direct replacement so of course the labor of installation will be allot less and you can still use your original intake and all other parts. NO MORE HEADACHES. I will keep you guys posted and when I get some dyno comparison numbers I will post them. This will definitely be something to look out for.
 

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First let me start off by saying that Rick is a very nice guy and knows what he is doing. He did some extra porting work on my heads.

With that said, I don't agree with him on this one. He has already done this on one car with a pretty poor result. But, this car could have other issues that I'm not aware of. No matter how you look at it, a ported PI head will out flow a ported NonPI head.

Here's that guys story:
http://forums.modulardepot.com/showthread.php?s=&threadid=815

and a follow up:

http://forums.modulardepot.com/showthread.php?s=&threadid=1066

Good luck!!
 

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Renegade Racing has been doing this for a little bit now, and they get better intake flow numbers from the ported NPI heads then they do the ported PI heads, but on the same note they get better exhaust flow from the ported PI heads then from the ported NPI heads.

Also, you will probally make a little more power with the ported PI head then with a ported NPI head because you are getting some power from the higher compression that comes with the PI head swap.

Each head has its place. Crunch the numbers, look at what you want to do, and choose accordingly.

Johnny Langton has a set done by Renegade, and i'm sure he will make a post in this thread.
 

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I do not agree,Ported Pi heads are better.I think the heart shape chamber is a better design than the 96-98.What are the flow numbers of the livenoise heads.Patriot Peformance CNC heads are the best value around.
 

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TWilkes said:
I do not agree,Ported Pi heads are better.I think the heart shape chamber is a better design than the 96-98.What are the flow numbers of the livenoise heads.Patriot Peformance CNC heads are the best value around.
And just why are they better? Just because thats what you have? At the very LEAST, the only reason most people like NPI heads is because of the lower compression, so just why do you like the heart shape better?
 

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svo heads

I would choose svo heads already they flow 215cfm out of the box and if ported well they are gonna out flow the ported pi heads you know. There are ups and downs really if you use pi heads you up your compression so it would be hard to you a supercharger with that much compression but weith svo heads it will stay the same the compression and you can boost your 4.6 .
 

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I read an article in one of the mustang mags where they did a flow test with the NPI and PI heads. the PI made more low-mid range power but the NPI heads out-flowed them on the top end, high rpm. i think i might just have my 98 heads ported because i want to do a turbo set-up.
 

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96BluOvl said:
You people still can't accept it, can you?
No, it looks like you can't accept it because you've bought P&P'ed PI heads, and they arn't so extrodinary anymore. Who was the biggest proponet of PI heads and denounced NPI heads? Thats right, SD Wheeler.
 

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NRL said:
And just why are they better? Just because thats what you have? At the very LEAST, the only reason most people like NPI heads is because of the lower compression, so just why do you like the heart shape better?
No dude,that's because it's what he sells..
Remember the patriot performance heads emails that everybody on MTC got? It was this guy..and I warned him not to let his spamming happen again over there.
JL
 

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The heads are the best value.I was offering my opinion over the debate between NPI & PI heads.Most P&P PI heads have the chambers reworked to a larger size of 46cc.Stack PI chambers are 42cc.This is just my opinion.
 
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