PI Headswap Write-Up

Discussion in 'SN95 4.6L Mustang Tech' started by 5spd GT, Aug 26, 2007.


  1. Winters98GT

    Winters98GT Whoop...whoop-whoop-whoop-whoop...GANGNAM STYLE!!! Founding Member

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    it's all about "modular"

    Parts based on a single design, so many of them are interchangable. The 4.6 was not designed for the mustang or to be a performance based motor, but as a modular design used in many vehicles.
     
    #21
  2. pilks

    pilks Member

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    i know its ancient but the link for PI Headswap Pictures doesnt seem to work for me..... fyi
     
    #22
  3. Fobra281

    Fobra281 New Member

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    I have a Romeo block ( npi) and Im putting Windsor heads on it (pi) so which head bolts do I use? :shrug:
     
    #23
  4. N8Dogg98

    N8Dogg98 Mustang Master

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    According to the write up you need windsor head bolts.

    Part number: 3L3Z-6065-AA - (20 bolts)
     
    #24
  5. tom70

    tom70 New Member

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    great thread!!
     
    #25
  6. Fobra281

    Fobra281 New Member

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    Thanks Im just triple checking at this point. Because someone told me Windsor head bolts wont work with a Romeo block.
     
    #26
  7. N8Dogg98

    N8Dogg98 Mustang Master

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    Haven't done it myself, but the write up clearly states that if you are installing windsor heads on the 96-98 stang (which is a romeo block) you need windsor headbolts.
     
    #27
  8. Fobra281

    Fobra281 New Member

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    That was my exact statement to the person that said that to me. Im going with the write-up.;) I cant wait !!!
     
    #28
  9. thyreaper

    thyreaper New Member

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    uhh valve cover problems

    i just got a set of pi heads and i took them to the machine shop and they came back that they are from a 01-04 mustang 4.6l but i counted the valve cover bolts and i only came up with 9 on each head, my stock seems to have like 10-12 cant really see too much stuff in way, but ya the heads i got seem to only have 9 on top where the valve cover sits unless im missing one somewhere that i didnt see, whats this about?
     
    #29
  10. thyreaper

    thyreaper New Member

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    lol no one knows? im counting the ones only on the top, are there any on the sides or anything that i dont see? i looked at some pics online and i counted 9 on those to so im sure im not counting right
     
    #30
  11. Sunset

    Sunset New Member

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    1999 and and most 2000 Mustangs have Windsor based engines and 2001-2004 have Romeo based engines. Windsor had 12 bolts holding the valve covers and press fitted cam gears. The Romeo engines had 9 bolts holding the valve covers and bolt on cam gears as did the 96-98 Romeo Non-PI engines. Hope this helps.
     
    #31
  12. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    :nice:
     
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  13. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    I went to the track a few years ago, after completing my PI Headswap and thought I would post up the results (untuned - just bolted on) from the PI Headswap.

    Before with Bone Stock NPI 1998 GT (5spd - 3.27 gears - 110k):

    2.356 - 60 ft.
    6.332 - 330 ft.
    9.647 - 1/8 ET
    74.89 - 1/8 MPH
    12.30 - 1000 ft. ET
    85.32 - 1000 ft. MPH

    After with 2002 PI Heads/Cams/Intake (5spd - 3.27 gears - 133k):

    2.159 - 60 ft.
    6.032 - 330 ft.
    9.255 - 1/8 ET
    76.98 - 1/8 MPH
    11.82 - 1000 ft. ET
    88.15 - 1000 ft. MPH

    Difference of:

    .197 - 60 ft.
    .300 - 330 ft.
    .392 - 1/8 ET
    2.09 - 1/8 ET
    4.80 - 1000 ft. ET
    2.83 - 1000 ft. MPH

    Same track, similar conditions, untuned. This gives a ballpark of what you can expect to gain with a NPI to PI Headswap.
     
    #33
  14. thyreaper

    thyreaper New Member

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    the info did help, the heads i have im guessing are romeo which means i can use my valve coverfs and all... they have removable cam gears on them to so im hoping the cams are stock.... im thinking of getting some adjustable cam gears so i can advance them 5 degrees or will it not make much of a difference? and what would that be in 1/4 mile before and after? with no tune
     
    #34

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