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  1. #1

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    what size pulley can i run stock?

    ok so me and robert (94gpgtp) took a 2 1/2 hour road trip on saturday to pick up some polished 5 spokes for him and a 3800 s/c & motor for me.

    well i think i got a pretty good deal on this motor, guy said it knocked but the s/c is in great shape with no play what-so-ever, and i did want an extra motor to rebuild so win-win!

    my question is what size pulley can i run with no mods cuz where as my pulley is over 4 inches this one is at 3 5/8? Now i heard i could run a 3.5 with no mods but ive never heard of a 3 5/8 pulley being used, knowing that its bigger i would think i could use it and not tare up the motor.

    fyi i think my s/c is shot so thats why i bought this one


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  2. #2
    Lurker 9lumina6's Avatar
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    with absolutely no mods....I would not run anything smaller than the stock 3.8'' pulley. It's just a ticking time bomb if you do. I still run the stock 3.8'' pulley on my regal with very light mods...and it still pulls plenty nice. I could even up the timing in it since it's running no KR but am too lazy to up it. I'm running a 3.4'' on my GTP but that has quite a few things done to it. I could more than likely run a 3.3'' safely on my GTP the way it is right now...but I like to stay conservative and I can always up the timing since it has no KR.

    Note......Added timing is free HP. And only when running no KR. you are most likely not going to be knock free with anything smaller than a 3.8'' (stock) pulley with no mods at all....especially no exhaust mods.

    2000 Grand Prix GTP.(1st Quarter 2011 COTQ winner)139K....13.225 @ 103.65mph
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  3. #3

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    if 3.8 is stock why does mine measure over 4"? we are going directly across end to end right?


    98 GTP Daily Driver (Minor mods, just for looks)

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  4. #4
    Lurker 9lumina6's Avatar
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    all stock s/c pulleys on any L67/L32 motors are 3.8''. that 4'' you are getting is probably measuring the diameter on the outer lip that contains the belt......any stock from the factory M-90 pulley is 3.8''

    2000 Grand Prix GTP.(1st Quarter 2011 COTQ winner)139K....13.225 @ 103.65mph
    2003 Tahoe Z-71 5.3 210k...(Daily Driver)
    1990 TGP 79k
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  5. #5

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    so what is the correct measuring points? which in turn would mean the pulley on the new s/c is probably a 3.5

    How do i eliminate kr & up timing


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    95 Cutlass Supreme Convertible (Project car in process)

  6. #6

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    How do you eliminate KR on a stock S/C 3800? CAI, U-bend delete, hi-flow cat, to name a few things. You won't be able to safely bump the timing you'd need all that plus probably some light porting and polishing of the S/C and LIM. Plus a tuner, of course.
    1991 Buick Regal GS - 121k - 3800 SI - 440T4/4T60 - White/Silver Two-Tone - Grey Sport Interior *DEAD*
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  7. #7
    94GPGTP's Avatar
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    Well I have the dhp tuner. I told Steve already that I want to eliminate his cat and u bend and shut the rear O2 off. A intake is easy enough to make. Anyone on this site have any pointers for tuning using dhp? I really don't know 100% how to use the tuning part of the software.

    And my guess is why that motor we picked up had a knock is because of the smaller pulley on a bone stock car.
    1996 Pontiac Grand Prix SE 3100/4T60-E (Black) Totalled
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    What can i say... I love Grand Prix's...

  8. #8

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    i dunno what your talking bout that motor we picked up has 500 hp easy


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  9. #9
    Addicted to eaton's Avatar
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    * scratches head* LOL FWIW, Stock cars on stock pulleys sometimes have KR* so i wouldnt go lower then a 3.8 on stock. Remeber, a 3.8 car will out run a 3.4 car Stock vs stock. What im saying is. Support the pulley be-for you put it on. The motor will thank you!

    http://www.clubgp.com/newforum/tm.as...mode=1&smode=1
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  10. #10

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    ok thanks now does anybody have a puller i can borrow?


    98 GTP Daily Driver (Minor mods, just for looks)

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