PI Swap vs. P&P'd 96-98 Heads

[ImportEater98]

I am getting ready to do my heads/cams this fall after the season finishes up. I have non PI heads and i plan on running boost through the car. I know the PI swap increases compression, and i don't want that. I do want better flowing heads, though. Would it be wiser to port/polish/3AVJ my current heads? If so what would i be looking to spend for the machine work (i know what the cams/springs setup already cost)? While Im on the topic, i hear headers are easier to do with the heads off the car, does this deem true for Long Tubes as well? Any input would be great. Thanks!

 

[Blev]

I am getting ready to do my heads/cams this fall after the season finishes up. I have non PI heads and i plan on running boost through the car. I know the PI swap increases compression, and i don't want that. I do want better flowing heads, though. Would it be wiser to port/polish/3AVJ my current heads? If so what would i be looking to spend for the machine work (i know what the cams/springs setup already cost)? While Im on the topic, i hear headers are easier to do with the heads off the car, does this deem true for Long Tubes as well? Any input would be great. Thanks!

I myself was wondering about this a few months ago. Not sure if this thread will help you or not.

http://forums.stangnet.com/showthread.php?t=424617

 

[ImportEater98]

great article, but still not everything i need to know. I am glad my theory is right about the compression part. Thanks for you help!

 

[vvzer0incvv]

Over of modulardepot.com there was a post a while back that stated that p&p npi heads flow just as well as pi heads. I know that steen racing advertises that they can make npi heads flow just as well as pi heads. IMO if you are going forced injection, ie super or turbo charger, the few hp difference between p&p npi and pi heads won't make that much difference because you will save compression with the npi. I saw somewhere that the hp gained from a pi headswap, when broken down, is gained from the intake and the cams and only 5 or 10 from the heads themselves. Hope this helps.

 

[ImportEater98]

Oh great. That makes me think twice about wasting money on new heads....i have heard the the PI intake doesn't fit well on NPI heads is this true?

 

[COramprat]

Oh great. That makes me think twice about wasting money on new heads....i have heard the the PI intake doesn't fit well on NPI heads is this true?

The ports do not match up but some have either matched the ports by 'building' a match with rtv/epoxy and using the NPI gaskets. Livernous has an adapter now the matches the NPI heads with the PI intake but the intake has to be modified to fit under the stock hood. THey shave the plenium mount to accomplish this. The entire kit is around 600 including the modified intake. I think I'm going with the P&P NPI's with the PI intake and cams in the future. Seems the way to go and you only lose a few HP, if any, compared with the PI head swap.

Check out this thread for the intake swap write-up
PI intake

PS. Think about doing the cam swap yourself. It is really not too hard. There are a few who have done it and found it not too difficult.

 

[Blev]

The entire kit is around 600 including the modified intake. I think I'm going with the P&P NPI's with the PI intake and cams in the future. Seems the way to go and you only lose a few HP, if any, compared with the PI head swap.

Kit is 650 and add another 30 or so for shipping. If you have an aftermarket hood, you can just get the plates for 300 bucks like I did and get the remaining parts at better prices. I think I paid around 550 for everything.
Also, the P&P NPI heads outflow the NON P&P PI heads. I say if your going to use a power adder down the road, stick with the non PI heads and get them P&P but that's just my .02

 

[mrvax]

NPI stock heads and a standard Vortech install can usually get near 300rwhp. You should go for getting the P&P NPI heads or just upgrade to PI. If you go the PI route, you can have the swirl dams removed to keep the compression at stock levels. I would personally go the PI route and forget the P&P to save some $.

 

[Blev]

NPI stock heads and a standard Vortech install can usually get near 300rwhp. You should go for getting the P&P NPI heads or just upgrade to PI. If you go the PI route, you can have the swirl dams removed to keep the compression at stock levels. I would personally go the PI route and forget the P&P to save some $.

Isn't it close to the same price having the swirl dams removed as it would be to get the P&P? That's not buying new heads either. So I would think spending the money on the PI heads and then spending the money on getting the swirl dams removed would be alot greater than just the non PI heads P&P. I could be wrong though.

 

[bierbelly]

Drop back and punt. If you're going to boost, why not consider the FRPP heads and intake? Yes, expensive, but probably the best route to go, especially since the intake is aluminum (if I recall correctly). Or, go with the PI heads, cut down swirl dams and a Bullit intake. Even better, and maybe cheaper, get a '99+ engine out of a wreck and install the Bullit intake.

 

[96SOHC]

Drop back and punt. If you're going to boost, why not consider the FRPP heads and intake? Yes, expensive, but probably the best route to go, especially since the intake is aluminum (if I recall correctly). Or, go with the PI heads, cut down swirl dams and a Bullit intake. Even better, and maybe cheaper, get a '99+ engine out of a wreck and install the Bullit intake.

Hey...just port and polish your own heads! Not that big of a deal. Here's a pic of my roughed in PI heads (obviously not finished).