Port and Polish NPI

Discussion in '96-04 - 2V Specific' started by Brian95SVT, Mar 14, 2007.

  1. Brian95SVT

    Brian95SVT Legend

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    Ok so i have been reading a lot of the threads of the debate about PI heads vs NPI heads and the cams and intakes and all that.
    Currently i have a PI Intake Manifold with NPI Cams and NPI Heads and was told by the local shop and some others on here that i would be best just porting and polishing my NPI heads and either stepping up the cams or keeping NPI ones if i didnt have the extra cash.
    feedback?

    also how much does porting and polishing run? i know there are "different stages" so

    any other feedback you feel is necessary that i need to know and/or include please feel free to throw you opinions in. i dont want to make this a HUGE debate so... try and keep it calm.
     
  2. 96gt226410

    96gt226410 Active Member

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    There is a company that does great port and polish jobs for NPI heads. I can't remember the name, but I'm sure someone on here does. NPI heads that are ported well flow great however the cost to port and polish heads is around $1,000 after labor and hardware. You can get a set of PI heads for around $500 or cheaper. If you have some extra cash, port and polish those heads instead. The cheapest way to make good power is just to swap the PI intake manifold and PI (or aftermarket) cams. I'm doing the whole PI swap myself. My car has 100,000 miles on it and the heads aren't in the best shape...
     
  3. Brian95SVT

    Brian95SVT Legend

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    actually ive heard that ported nPI heads, PI intake, and PI cams is cheaper then a full PI swap.
    i already have the PI Intake, all i need to do is port the nPI heads and get the cams..... im just trying to find out as much info as i can, not gunna be doing this anytime soon
     
  4. 96gt226410

    96gt226410 Active Member

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    I got all of the parts form my PI swap for $750 shipped to my door. And that includes every gasket, nut, bolt, and with some extra OE seals. Just the port and polish will cost more than that.
     
  5. Brian95SVT

    Brian95SVT Legend

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  6. 96gt226410

    96gt226410 Active Member

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    The heads and cams have 30,000 on them. The intake is new and so are all of the gaskets. I've gotten quotes for porting and polishing bare heads (no labor for disassembly or removal of heads) for $700 - $1,000 around me.
     
  7. quickstang_1994

    quickstang_1994 Well-Known Member

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    4.6 Cylinder Head Flow Data
    (Courtesy of Livernois Motorsports)
    Stock
    Lift in Inches '96 '01
    .100 46 54
    .150 66.6 78
    .200 84.5 98
    .250 103.5 119
    .300 121.3 135
    .350 134.7 145
    .400 147 156
    .450 159.4 161
    .500 170 166
    .550 176 168
     
  8. 96gt226410

    96gt226410 Active Member

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    NPI flows better than PI with a high lift cam?
     
  9. quickstang_1994

    quickstang_1994 Well-Known Member

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    yes
     
  10. 96gt226410

    96gt226410 Active Member

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    Stock NPI heads? I find that hard to believe. Why wouldn't everybody keep their NPI heads and buy a set of cams then?
     
  11. Adam

    Adam Member

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    Those NPI numbers are inflated....and the PI numbers are decreased compared to what I have seen. Livernois is also selling products like "adapters" to make NPI heads bolt on. Those numbers are also the intake side....take a look at the exhaust..its not even close. Get PI heads and cams....I have a set of PI cams for $125 and you should be able to pick up a set of heads fpr $300. Thats $425.....anyone who ports heads for that ought to slapped and sterilzed.
     
  12. quickstang_1994

    quickstang_1994 Well-Known Member

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    most people jump on a bandwagon that is the way people are. And it's easier to change everything plus the non pi heads can not use to big of a cam unlike the pi heads
     
  13. quickstang_1994

    quickstang_1994 Well-Known Member

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    I guess you think MM&FF who post bad info huh
     
  14. Adam

    Adam Member

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    I am not saying anyone posts bad numbers, but I believe the whole point of that write up was that NPI heads aren't as bad as once thought...correct?. I am saying those NPI numbers are inflated compared to what I have seen, AND those are INTAKE numbers only...do you know what the exhaust numbers look like? They look like shit...period. if you want to run NPI heads knock yourself out. There is no money to be saved by doing it. If you want to save money then keep the NPI heads and run a PI intake/cams..thats the cheapest way. Porting NPI heads is going to be more costly than a PI swap.
     
  15. quickstang_1994

    quickstang_1994 Well-Known Member

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    on one of the mustang web sites(not sure which one) but someone tested it and there was like a 5 rwhp difference and only switching heads(pi cams and intake).
     
  16. Adam

    Adam Member

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    Then use NPI heads. I am simply saying those numbers are inflated. So lets take my car for example, I made 247 rwhp with stock PI heads stock PI intake and VT cams through an auto with 4:10's(yes numerically higher gears do lower your dyno number, even though the torque multiplicatin is much higher on the track/street) So your saying that a NPI headed car with VT cams and a PI intake with make 242rwhp through an automatic trans???
     
  17. tooslow

    tooslow Active Member

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    i'm sure the 5hp diff was with STOCK PI cams, you should realize its going to be different with aftermarket cams. you're changing a mighty big variable, without a dyno, no one can answer that.
     
  18. quickstang_1994

    quickstang_1994 Well-Known Member

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    I ll more than likely be able to let you know the answer very soon but still deciding on the best combo to use.
     
  19. Adam

    Adam Member

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    I can answer that question for you right now. No freaking way. You are gonna come in bare minimum 10-15rwhp less. So PI heads cost $300-400, $300-400 for a true 10-15rwhp? Thats a cheap mod. People spend tons on junk like pulleys, TB's etc that add 2-3rwhp each tops. I know the guys that have made big power on NA NPI setups. It didn't just happen, it took time.
     
  20. quickstang_1994

    quickstang_1994 Well-Known Member

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