Stock bore, 1.900" intake valve ;)

Discussion in '96-04 - 2V Specific' started by 96blak54, Feb 7, 2016.

  1. 96blak54

    96blak54 Legend

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    This means roughly a 1.750" Internal Diameter of the valve seat, were as the stock npi is 1.590" and pi is 1.540".( typical over size valve is .040" more)

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    The pic shows an Chevy Ls 2.020" intake valve modified to 1.900".
    A bigger o.d. valve seat must be installed! The valve guide must be reemed from 7mm to 8mm. The valves tulip must be ground to the 1.900" diameter(this gains a good .040" margin!), ground to length and turned for chevy keeper grooves and 7mm o.d. tips to use stock followers. The easier scenario here would play favor in weight saving by using a valve with 7mm stem. Cost savings in machine works too. Such as this replacement valve offered by Trick flow for their tfs modular heads.

    http://m.summitracing.com/parts/tfs-52900211
    This valve is almost a direct fit. Stock valve guide honing may be necessary to open the I.d.

    Also needed is a set of offset location head dowls. You know...them things that line the head and gaskets up to the bores! These do-hickies shift the head .050". This allows for the big intake valve clearance to function. All other gasket aspects fall into place just like stock. Intake manifold may need elongated bolt holes...I have not explored this point yet. Cam sprockets can easily be align adjusted through spacers/shims....although I beleive their will be no need. .050" of an inch is less than a 16th. Front cover gasket should have enough material to compensate the .050" shift.

    [​IMG]

    Now most folks will blab out about increased valve shroud. Ok I agree.....the stock valve is over 50% shrouded....25% is cylinder bore wall, 25% swirl dam.(offset head dowls heppens to be an old trick drag racers used to shift the intake valve away from the cylinder walls aiding in un-shrouding the valve) I would agree with anyone about valve shrouding on a normal high approach cylinder head(like 95% of heads available...even them chevys) where the valve angle favors the intake side of the head causing the valve tulip to become an interference. This 360° of valve un-shrouding plays favor to flow. NOT in a modular 2v head were the intake and valve tulip together are in line allowing for a straight shot charge.(no interference) This is why the valve angle favors to the exhaust side and sparkplug placement is on top! Staight shot intake ports! Create 100% in cylinder swirl motion those interference head dream of! Welcome to the nondetonating modulars! (Insert compression ratio here____)

    Here is the kicker! Since the pi head has the larger exhaust valve, this topic does not play favor cause head material is missing where the headgasket needs. UNLESS!!!.....the use of fel-pro's permatex headgaskets 9792PT2. These HG allow for serious shift, but crush .050" so build accordingly!

    This has been my latest R&D. Since sn95forums loves me so, I figured sharing with my family was only right! Enjoy!!
     
  2. BMAC96GT

    BMAC96GT Active Member

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    That valve is massive lol
     
  3. 96blak54

    96blak54 Legend

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    Yes it is!

    And im quite surprised no-one has debated the "bigger valve adds shrouding" thing. All suggestions welcomed!

    Also! Im adding this to the first post, the link posted for trick flow head specific valves will not work in pi heads because of shorter overall length. Although a solution is to use modified LS valves or special made valves.
     
  4. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    My heads came with those trick flow valves.

    [​IMG]


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  5. 96blak54

    96blak54 Legend

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    Yes they did!
     
  6. ttocs

    ttocs Legend

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    there is just something about trickflow to me. I have not regretted their heads on my 94 for a second since they were installed.
     
  7. 96blak54

    96blak54 Legend

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    They are nice heads! The port geometry is classic, but they flow like mad. Im curious how they perform in an all out scenario.
     
  8. ttocs

    ttocs Legend

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    am curious to know what an "out out" senario is? Are they comming out of the closet?
     
  9. 96blak54

    96blak54 Legend

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    Lol...yea I just corrected that!
     
  10. Mustanger

    Mustanger Well-Known Member

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    Seems like Trick Flow is very popular...I always wonder how they compare to the AFR Renegade heads? Why do I not see or hear as much about the AFR's? Is it because TF makes a nice integrated whole package? I am leaning to the AFR Renegade 165 heads for my build of a 306...
     
  11. 96blak54

    96blak54 Legend

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    To bad AFR doesnt make a 2v modular head. I dont see how they could make one better. The competition would be inviting!
     
  12. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    We need a dislike button in here...... I don't like droptop anymore.
     
  13. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    But think about how awesome my kids pink mustang will be with these installed.
     
  14. OLD H2S

    OLD H2S Well-Known Member SN95 Supporter

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    I am with you, I will do this on my old NPI when I get them off. I will put on the PI custom heads on to see what the numbers are, I am moving slow, zero here this morning.
     
  15. 96blak54

    96blak54 Legend

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    Lol....at least you are moving slow! Ive been moving backwards!
     
  16. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    I'm bringing this back to the top, hoping to see some more info in here soon.
     
  17. 96blak54

    96blak54 Legend

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    Oh yea.....what are you hoping to see? High compression 5.4l with big intake valve npi head? Ill be honest......im hoping too.
     
  18. OLD H2S

    OLD H2S Well-Known Member SN95 Supporter

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    With a rear turbo and copper tubing to the intake manifold..