Hypothetically: What route would produce more power? - Page 2 - Ford Mustang Forum
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I wasn't trying to be an a$$ but it has been said over and over and over......do I need too say again? Ok I'm not goin back to copy post links and shits but someone told you something around the lines of "if there was a cheap way to skimp out and end up with more power don't you think everyone would know". I don't have much of a problem with you cause I.understand we can all be a bit stubborn at times. I'm pretty sure I was correct on what I have said but if you wana know for sure what's gonna make more power/be the better choice and be cheaper. Just give Nick a call at MHS and ask him yourself. I'm no head geak but I would have to say stock ported heads with a good cam is going to be limiting the potential of the cam. So answer me this.....what is the big deal with breaking loose a few head bolts while at it replacing head gaskets, timing chain set, adjustable cam gears. I don't know why you got all butt hurt from my post but everyone has been trying to tell you. I promise that you would be cussing trying to fight those valve springs with the heads on. Also leaving the heads on is it honestly gonna be worth leaning over the car to do all this work? Sorry pal I'll stay out out of your thread soo you don't get your feelings hurt.

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ok, just for the record, I'm 17.

if 500$ is alot to you, stop worrying about modding your car. 500$ isnt alot to me, and I'm not from money.

YOU need to stop getting on peoples(fordman666) ass because he is giving you the truth.


I'll tell you straight up, I have rebuilt alot of heads, and rebuilding them OUTSIDE of the car is a huge PITA IMHO. imagine that inside the car. also, have you ever bent over at a 65 degree angle for 8 hours? no? I get so much pain in my back from bending over my fender I walk into any job with a stomache full of narcs. (on going back problems, legally prescribed medicine)


I'm with ford man here..you either have never had to go that far into an engine before or are walking into this with a huge ego.

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post #18 of 27 (permalink) Old 03-04-2012 Thread Starter
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Quote:
Originally Posted by kids96gt View Post
ok, just for the record, I'm 17.

if 500$ is alot to you, stop worrying about modding your car. 500$ isnt alot to me, and I'm not from money.
Well you're tight.

I think everybody is missing the point here. Yeah I'm probably going to get attacked for this too. But my OP was based off of Bullitts post. Which shows that NPI heads outflow PI heads with higher lift cams. I was unsure about the issue in the first place... Thats why Hypothetically was in the title. It would be different if I said "HEY GUYS LOOK AT TH1S S1CK SH1T I FOUND ON THE 4UMS! IM GUNNE GET LIKE 400HP."

No, I asked for clarification.

I am sorry if it is a stupid question to some of you guys. I realize it would be the same as my girlfriend trying to understand my ramblings about my engineering courses. But I sure as hell do my best to explain things to her.

Some of you guys forget that we're not all experts.

I just dont get why this thread constitutes rudeness and brutal honesty towards me. Fordman, you had a really constructive post within yours :

"NPI heads have different needs than PI heads so we offer NPI specific cams. NPI heads have much more piston to valve clearance than a PI engine, this allows more freedom in camshaft design. They have more restricted exhaust ports so the exhaust duration is made longer to compensate. The 525 intake lift cams will work on stock NPI heads, the 550 lift version will need raised retainers on the intake valves or other modification to work. 500 exhaust lift is used for Stage 1 and 2 as the stock exhaust port stalls at 400 lift. All NPI NA cams are designed to use the stock NPI valve springs up to 6500RPM, above that upgraded valve springs are highly recommended."

Thats ALL I was asking for. If you would have just posted that in the first place I would have said Thanks with a big fat thumbs up. Instead I just have a bitter taste in my mouth about it.

Black with saddle 1996 Mustang GT convertible. Manual. NPI, 2v 4.6L. Full bolt-ons.
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Your thinking regarding the NPI heads flowing better than the PI heads is not correct. SORRY
When flowing heads it's called "area under the curve".
By your own chart the PI heads flow better at EVERY lift value until you get to .500". The reason you get more power out of the PI heads is because the cam is only at maximum lift for a micro second. Most of the time it's either ramping up or ramping down from maximum lift number. So the 4-5 cfm more you get from the NPI heads at max lift doesn't make it a better head. The flow differences at the lower lift numbers are HUGE in favor of the PI heads.
If it wasn't, Ford would never have changed them in the first place.
MOST of the 45 HP increase from the '98 to the '99 cars 215 vs 260 comes from the better flowing heads and intake. Do you understand what I'm trying to say.

It's the same thing as when someone puts the biggest carb they can on their car, then a car with a smaller carb spanks them. Again the motor only uses the last 100 cfm of flow at maximum rpm. The car spends WAY MORE time at a lower rpm accelerating through the gears. As soon as you hit maximum rpm YOU SHIFT and rpm falls back 2-3000 rpm where the smaller carb has better velocity/response through the venturi. This creates more TORQUE, which is what makes a heavy car with a small motor (Mustang) accelerate faster.

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Here is some reading mat'l. Compare the flow charts below to the flow chart in your fist post, on the stock NPI vs the PI. The exhaust port on the NPI head has a major restriction, and porting this area will cause a weaker valve guide area. Porting NPI heads is a lot harder an will costs more then the PI heads to get them to flow correctly.
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.
Mods = None. (well maybe just a few)
DB-Performance Tune: 634rwhp @ 6000rpm , 609rwtq @ 4000rpm, (500rwtq @ 2500rpm)

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Not to bust your balls Willy but the price is the same between the NPI and PI heads from Nick at MHS!

Life is to short to live it pissed off cherish who and what you got while you can!
Free speech isnít so free when it comes to protected classes and races, is it?
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My wife already shopped them off a long time ago. So, their price includes porting the choke down area in th mid section of the runner. might want to double check that one.

.
Mods = None. (well maybe just a few)
DB-Performance Tune: 634rwhp @ 6000rpm , 609rwtq @ 4000rpm, (500rwtq @ 2500rpm)

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Sure take a look at the links......unless there website is wrong!!

Modularheadshop PI heads

Modularheadshop NPI heads

I mean I could be looking at something wrong I have had only 3.5 hrs of sleep in the past 27 hrs and still having problems from my wisdom teeth beeing removed tomorrow will be 3 weeks from the day they was removed. I'm not too happy with the results of my one out of 3 teeth that was removed.

Life is to short to live it pissed off cherish who and what you got while you can!
Free speech isnít so free when it comes to protected classes and races, is it?
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post #24 of 27 (permalink) Old 03-04-2012 Thread Starter
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Quote:
Originally Posted by willyg1997 View Post
Here is some reading mat'l. Compare the flow charts below to the flow chart in your fist post, on the stock NPI vs the PI. The exhaust port on the NPI head has a major restriction, and porting this area will cause a weaker valve guide area. Porting NPI heads is a lot harder an will costs more then the PI heads to get them to flow correctly.
Those pics you attached are infinitely helpful. THANK YOU.

PS. What book is that? I must have it.

Black with saddle 1996 Mustang GT convertible. Manual. NPI, 2v 4.6L. Full bolt-ons.
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its either the ford 4.6/5.4 rebuild book or the SHM 4.6/5.4 performance book. both found at barnes and nobles in the car section...

I think its the first book i listed.
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Quote:
Originally Posted by burninrock24 View Post
Those pics you attached are infinitely helpful. THANK YOU.

PS. What book is that? I must have it.

Great book, a must have.


BARNES & NOBLE | How To Build Max-Performance 4.6-Liter Ford Engines by Sean Hyland, CarTech, Incorporated | Paperback

.
Mods = None. (well maybe just a few)
DB-Performance Tune: 634rwhp @ 6000rpm , 609rwtq @ 4000rpm, (500rwtq @ 2500rpm)

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Quote:
Originally Posted by fordman777 View Post
Sure take a look at the links......unless there website is wrong!!

Modularheadshop PI heads

Modularheadshop NPI heads

I mean I could be looking at something wrong I have had only 3.5 hrs of sleep in the past 27 hrs and still having problems from my wisdom teeth beeing removed tomorrow will be 3 weeks from the day they was removed. I'm not too happy with the results of my one out of 3 teeth that was removed.

Not saying they are anyone is wrong, just saying to check and make sure this area is included in the porting.

.
Mods = None. (well maybe just a few)
DB-Performance Tune: 634rwhp @ 6000rpm , 609rwtq @ 4000rpm, (500rwtq @ 2500rpm)

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