stock npi heads p/p?

[freefallin98]

Ok, here is the question that has been on my mind. Would it be a good call to get my npi heads ported and polished? But the big questions is, what cams could I throw i nthose p/p heads, along with a p.i. intake? Please let me know if this would be a cheaper, or better route to go than the full p.i. swap route. Also, keep i nmind that I want a pretty lopy cam at idol. So either way, im prob going wit ha st. 2 camshaft. EVERYONE who knows or has experienced that, please chime in!

Thanks,
Free

 

[QTRHRSE]

well i went the full PI swap... PnP'd and i loved it.

but from what i hear the NPI heads do very well Ported as well, as long as you have the PI intake

i used Comp XE274 cams and thought they were great. LOPED at idle for sure!!!!!!!
pulled very nice as well, esp. above 3500.

 

[freefallin98]

Nice, I heard that there are really only 2 sets of cams from comp that ca nbe used on npi heads. Does anyone know what they are? Any other brands that offer a npi cam without modifying to fit?

 

[Johnny Langton]

You can run up to a .550" lift cam in a NPI head with the offset retainers offered by Crower.
I'm using the Comp 270AH cams in my NPI's-they work very well.
JL

 

[steedastang]

i'd say go for it. I've heard ported npi heads flow about the same as ported pi heads (combustion chamber work). If i were you i would have the new trick flow intake portmatched to it. just take it into the person doing the port work on the heads and they should be able to do it.

I just put in crower stage 3 npi cams and they make pretty good power and run smooth and perfect. there is a nice lope at idle and it even idles smooth (not one stall or even stall etempt) but you may want to go with a pi cam with some offset retainers as mentioed before.

 

[freefallin98]

yeah but I want a really lopy cam..so people know my car is fast lol. So what im saying is a guess that as of right now, im thinking of having my npi's ported and I am going to run them with like a stage II Comp Cam and PI intake. How much could I expect to pay for a goop P & P?

 

[MustangMatt96GT]

I can get you pricing on port and polish work, along with a valve job. PM if interested

 

[voidfinger]

i'd say go for it. I've heard ported npi heads flow about the same as ported pi heads (combustion chamber work). If i were you i would have the new trick flow intake portmatched to it. just take it into the person doing the port work on the heads and they should be able to do it.

I just put in crower stage 3 npi cams and they make pretty good power and run smooth and perfect. there is a nice lope at idle and it even idles smooth (not one stall or even stall etempt) but you may want to go with a pi cam with some offset retainers as mentioed before.

Yea they might flow the same on the intake side... i've never seen a set of npi heads even with exstensive p&P work flow that well on exaust. I could be wrong but i've never seen it.

 

[Johnny Langton]

i'd say go for it. I've heard ported npi heads flow about the same as ported pi heads (combustion chamber work). If i were you i would have the new trick flow intake portmatched to it. just take it into the person doing the port work on the heads and they should be able to do it.

I just put in crower stage 3 npi cams and they make pretty good power and run smooth and perfect. there is a nice lope at idle and it even idles smooth (not one stall or even stall etempt) but you may want to go with a pi cam with some offset retainers as mentioed before.

Yea they might flow the same on the intake side... i've never seen a set of npi heads even with exstensive p&P work flow that well on exaust. I could be wrong but i've never seen it.

N/A they really don't have to....75% is a good flow ratio intake to exhasut,and ported NPI's are right around that orjust more than that, whereas ported PI's are around the 85% mark. That's good for power adders, but actually does no good N/A. My heads flow mid-220's cfm intake and right at 180cfm exhaust.
JL

 

[voidfinger]

i'd say go for it. I've heard ported npi heads flow about the same as ported pi heads (combustion chamber work). If i were you i would have the new trick flow intake portmatched to it. just take it into the person doing the port work on the heads and they should be able to do it.

I just put in crower stage 3 npi cams and they make pretty good power and run smooth and perfect. there is a nice lope at idle and it even idles smooth (not one stall or even stall etempt) but you may want to go with a pi cam with some offset retainers as mentioed before.

Yea they might flow the same on the intake side... i've never seen a set of npi heads even with exstensive p&P work flow that well on exaust. I could be wrong but i've never seen it.

N/A they really don't have to....75% is a good flow ratio intake to exhasut,and ported NPI's are right around that orjust more than that, whereas ported PI's are around the 85% mark. That's good for power adders, but actually does no good N/A. My heads flow mid-220's cfm intake and right at 180cfm exhaust.
JL

That means you got some seriously flowing heads there dude. I've never seen one flow 180 cfm exhaust. I think the most i've seen was like 165 cfm... learn something every day

Well the 85% mark would probably be good with about a 150 shot of no2 bwahaha

 

[MustangMatt96GT]

ea those are decent numbers for NPIs but i have seen some that are a little better. When done properly NPIs are better for a n/a motor, but because nitrous loves compression inurge any nitrous users to do ported andpolished PIs.

 

[freefallin98]

Yea im def. going to stay n/a. I dont want a race car lol. Im all about practicallity and driveability. I want something that get get me safely into the mid 13's. I think porting my npis is going to be a good route to go. What cam should I go with if a want a really lopy idol?

P.S. I will not be doing this 'til the summer.

 

[Johnny Langton]

ea those are decent numbers for NPIs but i have seen some that are a little better. When done properly NPIs are better for a n/a motor, but because nitrous loves compression inurge any nitrous users to do ported andpolished PIs.

\
My head's flow numbers aren't inflated at all like alot of places do to get big numbers. It's with a true 3.55" bore plate,and a clay radius on the intake and exhaust.
They apparently work well-my et's in the 3600lb car are testament to that.
JL

 

[voidfinger]

Yea that has to be a hellava set up to run that on a tbird

Is it N/A or n20 or anything?

 

[Johnny Langton]

Yea that has to be a hellava set up to run that on a tbird

Is it N/A or n20 or anything?

It's N/A,no power adders on my car at all.
JL

 

[DropTopPony]

ea those are decent numbers for NPIs but i have seen some that are a little better. When done properly NPIs are better for a n/a motor, but because nitrous loves compression inurge any nitrous users to do ported andpolished PIs.

\
My head's flow numbers aren't inflated at all like alot of places do to get big numbers. It's with a true 3.55" bore plate,and a clay radius on the intake and exhaust.
They apparently work well-my et's in the 3600lb car are testament to that.
JL

Are your heads done be Renegade?

 

[Johnny Langton]

ea those are decent numbers for NPIs but i have seen some that are a little better. When done properly NPIs are better for a n/a motor, but because nitrous loves compression inurge any nitrous users to do ported andpolished PIs.

\
My head's flow numbers aren't inflated at all like alot of places do to get big numbers. It's with a true 3.55" bore plate,and a clay radius on the intake and exhaust.
They apparently work well-my et's in the 3600lb car are testament to that.
JL

Are your heads done be Renegade?

Yes,Jim did my headwork.
JL

 

[voidfinger]

ok so you running a built intake with npi p&p heads... with a comp 270 i think... do you have higher CR than stock or somthing.. i'm just having a hard time seeing a heavy tbird with a 4k stall doing a 12.1 .... It's not that i'm doughting but there is something there that not clicking with me lol. :thumb:

 

[Johnny Langton]

ok so you running a built intake with npi p&p heads... with a comp 270 i think... do you have higher CR than stock or somthing.. i'm just having a hard time seeing a heavy tbird with a 4k stall doing a 12.1 .... It's not that i'm doughting but there is something there that not clicking with me lol. :thumb:

My car is a real street car.
Leather seats,CD stereo with 3 amps and a single 10" sub.
4.30 gear
4000 stall converter
Kooks mid-length headers
2.5" Magnaflow duals with cats
Ported Bullitt intake
Ported NPI heads
Comp 270AH cams
Steeda underdrive pullies
It's an aluminum Explorer block
Ross flat-top pistons with approx 10.5:1 CR
Cast Mark VIII crank
Manley Promaster I-Beam rods
Billet oil pump gears in a 2V pump from TSS in Orange,Tx
80mm '00 Lightning truck MAF
Custom tune
Custom air inlet tube
Stock suspension(most of it has almost 250K miles on it,and the only parts that are different are just stock replacement pieces)
NO power adders
and it weighs right at 3600lbs.

It is what it is. Believe it or not.
JL

 

[Jrgunn5150]

I've tld you guy's before, even though no one beleived me... A buddy back in Ohio had a Stang, NPI with PI intake cams, Jmod, converter, and alot of suspension work who managed to touch the nigh 12's, and hit low 13's all day long.