1998 NPI Mustang with 2.1 KB

Casper98GT · March 21st, 2007, 10:42 AM

Ok, so i have installed PI intake and cams on the NPI. Have all bolt ons, control arms, clutch, driveshaft..the list goes on. Also have 80shot of nitrous.

All the dyno charts i have found online on other forums and such show that the heads are the worthless point on a PI swap.

So i was wondering if the NPI heads flow decently enough to put a KB 2.1 on my 98. Just stick to the 9psi pulley. And since im getting rid of the intake to swap to the KB intake the cams are already there so i wonder how much power it would be making over a stock NPI motor.

Just an idea, i was wondering if anyone else on these boards had a NPI mustang with a KB on it. Without the raised compression of the PI heads

Boomer · March 21st, 2007, 11:34 AM

I do not have the BK but have a little insight. The only down fall to the P.I head is the shortside raduis (that thing is ugly). The P.I heads have more intake runner volume than the npi however the npi have higher air velocity. The P.I will probably be the better of the two heads to run on a KB, the forced air overcomes the shortside on the P.I.. Now if you wanted to try something cool have the npi ported running the KB, you'll surely exceed the limits of the factory shortblock. I think you'll be neck and neck with a P.I KB car IMHO.

Casper98GT · March 21st, 2007, 11:52 AM

Well, thanks for the reply. I was thinking if i got the good gains from just intake and cams from a pi motor. Then why not shoot for the 2.1 big bore kit they sell for a 96-98 GT. Then i should be around the same power as a PI car is.

But they i got to thinking about the possibility of a PI head out performing a NPI head. But either way if i ditched the PI cams and got blower cams made for the KB i could be in front of a PI car with a KB on it. Only pulley for this kit is a 9 psi that it comes with. And 9 would be more then enough due to the block. Im sure i would be making close to the threshhold of the block anyways.

I dont plan on going PI heads anyways due to the high compression of the pi heads and seeing 10.5:1 after the PI swap i think i would have headlift problems anyways. So thats why i wondered NPI heads. If they would flow good enough then i wouldnt need to go any head work, but if i got greedy and wanted more power i would do headwork.

I cant seem to find a single person alive with a NPI mustang and a KB on top. None the less with PI cams.

Boomer · March 21st, 2007, 12:05 PM

I think it would be a great idea, I would like to see what numbers it would put down. Keep me posted if you go that route, I'm curious

....

DragonFreak · March 21st, 2007, 12:40 PM

from what i have read if you have the non pi heads fully ported they are exactly like the pi heads in flow and volume...just with lower compression....i have been doing research on this for awhile due to the fact that i have both a set of pi and non pi heads right now i can look around and see what i can find for ya.

Casper98GT · March 21st, 2007, 01:27 PM

yeah im running a small shot of nitrous right now and i want to get a form of F.I. that i dont have to keep paying for. But it is fun being able to run a 13.8 with a N/A NPI car.

nHuman · March 23rd, 2007, 06:24 AM

how much does it cost to refill ur bottle?

Casper98GT · March 23rd, 2007, 07:28 AM

35 bucks at the drag way

March 21st, 2007, 10:42 AM	#1
Casper98GT Hardcore Enthusiast Join Date: Aug 2005 Location: NEW HAMPSHIRE Posts: 2,393 iTrader: 0 reviews	1998 NPI Mustang with 2.1 KB Ok, so i have installed PI intake and cams on the NPI. Have all bolt ons, control arms, clutch, driveshaft..the list goes on. Also have 80shot of nitrous. All the dyno charts i have found online on other forums and such show that the heads are the worthless point on a PI swap. So i was wondering if the NPI heads flow decently enough to put a KB 2.1 on my 98. Just stick to the 9psi pulley. And since im getting rid of the intake to swap to the KB intake the cams are already there so i wonder how much power it would be making over a stock NPI motor. Just an idea, i was wondering if anyone else on these boards had a NPI mustang with a KB on it. Without the raised compression of the PI heads __________________ 91 LX, 5spd. Ex:Toyota/Ford tech Marine Machinery Technician, Department of Defense.

March 21st, 2007, 11:34 AM	#2
Boomer Enthusiast Join Date: Oct 2006 Location: warren, Mi Posts: 941 iTrader: 0 reviews	I do not have the BK but have a little insight. The only down fall to the P.I head is the shortside raduis (that thing is ugly). The P.I heads have more intake runner volume than the npi however the npi have higher air velocity. The P.I will probably be the better of the two heads to run on a KB, the forced air overcomes the shortside on the P.I.. Now if you wanted to try something cool have the npi ported running the KB, you'll surely exceed the limits of the factory shortblock. I think you'll be neck and neck with a P.I KB car IMHO. __________________ Just another 10 second Mustang, what did you expect ? http://youtube.com/watch?v=BgykaUrmfvM

March 21st, 2007, 11:52 AM	#3
Casper98GT Hardcore Enthusiast Join Date: Aug 2005 Location: NEW HAMPSHIRE Posts: 2,393 iTrader: 0 reviews	Well, thanks for the reply. I was thinking if i got the good gains from just intake and cams from a pi motor. Then why not shoot for the 2.1 big bore kit they sell for a 96-98 GT. Then i should be around the same power as a PI car is. But they i got to thinking about the possibility of a PI head out performing a NPI head. But either way if i ditched the PI cams and got blower cams made for the KB i could be in front of a PI car with a KB on it. Only pulley for this kit is a 9 psi that it comes with. And 9 would be more then enough due to the block. Im sure i would be making close to the threshhold of the block anyways. I dont plan on going PI heads anyways due to the high compression of the pi heads and seeing 10.5:1 after the PI swap i think i would have headlift problems anyways. So thats why i wondered NPI heads. If they would flow good enough then i wouldnt need to go any head work, but if i got greedy and wanted more power i would do headwork. I cant seem to find a single person alive with a NPI mustang and a KB on top. None the less with PI cams. __________________ 91 LX, 5spd. Ex:Toyota/Ford tech Marine Machinery Technician, Department of Defense.

March 21st, 2007, 12:05 PM	#4
Boomer Enthusiast Join Date: Oct 2006 Location: warren, Mi Posts: 941 iTrader: 0 reviews	I think it would be a great idea, I would like to see what numbers it would put down. Keep me posted if you go that route, I'm curious .... __________________ Just another 10 second Mustang, what did you expect ? http://youtube.com/watch?v=BgykaUrmfvM

March 21st, 2007, 01:27 PM	#6
Casper98GT Hardcore Enthusiast Join Date: Aug 2005 Location: NEW HAMPSHIRE Posts: 2,393 iTrader: 0 reviews	yeah im running a small shot of nitrous right now and i want to get a form of F.I. that i dont have to keep paying for. But it is fun being able to run a 13.8 with a N/A NPI car. __________________ 91 LX, 5spd. Ex:Toyota/Ford tech Marine Machinery Technician, Department of Defense.

March 21st, 2007, 12:40 PM	#5
DragonFreak Regular Join Date: Aug 2006 Location: Virginia Posts: 418 iTrader: 0 reviews	from what i have read if you have the non pi heads fully ported they are exactly like the pi heads in flow and volume...just with lower compression....i have been doing research on this for awhile due to the fact that i have both a set of pi and non pi heads right now i can look around and see what i can find for ya.

March 23rd, 2007, 06:24 AM	#7
nHuman Regular 2003 Cobra Join Date: Dec 2006 Location: High Point, NC Posts: 306 iTrader: 0 reviews	how much does it cost to refill ur bottle?

March 23rd, 2007, 07:28 AM	#8
Casper98GT Hardcore Enthusiast Join Date: Aug 2005 Location: NEW HAMPSHIRE Posts: 2,393 iTrader: 0 reviews	35 bucks at the drag way __________________ 91 LX, 5spd. Ex:Toyota/Ford tech Marine Machinery Technician, Department of Defense.

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