ORIGINAL: yoteehunter

http://forums.modulardepot.com/4-6l-...-npi-data.html

Here is the real math. The fact is that I got a set of non pi heads for free so far I have no reason to go buy pi heads as I feal I can save money and get the same results. I am out to show non pi. My first build was to show that I could make good power through stock non pi heads, and I have acomplished this. Now I am going to try to reach my power goals with non pi heads still. If it doesnt work I will switch to pi but so far I have met my goals. I will know soon enough. Personally I feel the intake is the biggest hold back and the heads are not the biggest restriction, however once the intake is swapped they can become the holding factor on power. But over all I have pretty much maxed out the stock internals as far as there strength so me initially swapping to pi heads first would have been a waste of time and money.

ORIGINAL: 2000GT4.6

if you read thru the entire thread there is ALOT of disagreement with what he is saying. Everything I have seen shows the ported PI heads coming out on top.

Not to mention that its hard to get ahold of a ported/worked NPI setup, that is to say with larger valves etc. I guess if you are going to do all the work yourself.

Common sense and all the data I have seen leads me to beileve that NPI<PI<ported NPI< ported PI is the way it works.

So far as hand porting... well good luck but I have never heard of anyone having much luck with this.

I just don't see the allure of staying NPI. You already are buying a new shortblock (forged internals anyway) to make big numbers, why not go ahead and get the PI heads for a couple hundred and have them ported? Not only will they (IMO) outflow the ported NPI heads, they also have a varaity of intake manifolds availble without having to resort to adapter plates.

ORIGINAL: silverstang1996

it's big money to get a aftermarket intake though, if you mean something like custom made, like the reichard racing intake is around $1500 i believe, if you meant typhoon/trickflow then that'd be better, anything is better than that sh!tty plastic intake..

ORIGINAL: yoteehunter

I am building my own short block. Im just going to buy a rotatong kit and do the rest myself. There is no way Im forking over $3000-4500 for a pre built short block when I can peice my own together for about 3/4 the cost or even less. Also most company's still hand port there heads. Renegade racing, Powerheads, as well as others are all hand ported heads. Just because they say they are cnc'd doesnt mean that a machine cut them. To cnc heads mearly means that each port and chamber has been tested to be the same and flow the same, unless they are cnc cut. There is absolutely nothing wrong with hand porting heads. Either way to simply get the heads ported is 500-900 dollars for just the port job. This again is to much money and I can do just as good of job and test them on a flow bench and get the same results as any big head porting company for simply the cost of my own labor. I am not trying to argue the fact that npi is "great" I am simply trying to show that the npi heads can make as good of power if done correctly and money can be saved. I see so many people throughing money into there cars buying this or that to make them faster. Some people can barely afford the gas to drive. I am merly trying to show what kind of power can be had by using my head and building something nice for myself, rather than using my wallet and buying something nice for myself. I have already built the 400hp twin turbo kit for $1800.00. I just skipped the 7000.00 bucks every turbo kit wants to charge because they claim they must recover R&D. Wich is bull when I think about how easy it would be to sent my turbo pipes off to a mandrel company and have kits made like there is no tommarow. My goal is to end up with a car that can run with supercars, yet cost only fractions of what they do. I just get my kicks when someone ask, "what the hell did you do to that car, where did you get that?" when I say I built it there is something about that wich makes me proud.