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Cam for 350 TBI

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Charly, Mar 29, 2002.

  1. Charly

    Charly Registered Member

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    hey,

    I'm thinking about putting in a 'different than stock' cam when I do the rebuild (which will be soon).

    It's an 89 350 TBI, non-roller, for now I'll keep the stock manifolds and heads. I obviously want torque at or near idle and up to about 4500 at least. I realize the stock cam would be near perfect, but was wondering if I could go one step up.
    I hear staying at 112* LSA is best, but I'm not sure if these 111" (one was recommended directly by Comp, but they said it was 112, there spec card says 111) cams will be Ok.

    Here are four that I am considering (all Comp) duration is at .050:

    PN 12-304-4, 201/206, 406/406, 111

    PN 12-388-4, 206/212, 425/440, 112

    PN 12-249-4, 206/212, 434/444, 112

    PN 12-231-2, 206/214, 432/453, 111

    Stock (I hear) is about:

    194/203, 395/415, unsure on LSA

    Comparing 12-388-4 vs. 12-249-4, for example, would more lift with same duration be better for the lower end?

    All the Comp cams are rated at 1000-5000 rpm, except for 12-304-4 which is idle to 4700.

    Concensus seems to be that the duration and lift of all of these will be fine with the stock chip, not sure about that LSA tough.

    Tranny will be NV4500 (w/ 6.34 first) with 4.88s and 38s for wheeling, 35s street/winter. This will be primarily a crawler, with some street duty


    Your thoughts?

    thanks,

    Charly
     
  2. solowookie

    solowookie 1/2 ton status

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    I am in the process of finishing my engine up, and I'm using PN 12-249-4, 206/212, 434/444, 112 so I can let you know how I like it.
     
  3. Charly

    Charly Registered Member

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    Thanks.

    When will you have that in and running?

    Stock chip?
     
  4. solowookie

    solowookie 1/2 ton status

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    in about a week - week & a half...
     
  5. solowookie

    solowookie 1/2 ton status

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    FYI these cam's are advanced 5 deg. by the manufacture when lining up the marks you are advanced...
     
  6. wayne

    wayne 3/4 ton status

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    I would also be interested in knowing how it works. I will be building an engine for my 89 either late this year or next spring providing this one lives that long. /forums/images/icons/smile.gif
     
  7. solowookie

    solowookie 1/2 ton status

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    yea well this is the second TBI engine I've built in the last 6 months or so; I can let ya know which one I like the best etc.
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I have this cam: PN 12-231-2, 206/214, 432/453, 111

    It's great. Mine is in a 305 and it makes torque right off-idle to about 4500 or so RPM. It's a great cam, but,

    it won't work with TBI. You need a cam specifically designed for fuel injection to avoid problems. 111* LSA isn't going to work with a MAP sensor. Sorry man, take a look at a Compucam or something.

    PN 12-249-4, 206/212, 434/444, 112

    Might work and be similar.

    Keep in mind, generally, lift=torque, duration=RPM.
     
  9. Charly

    Charly Registered Member

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    Actually, Comp stated that that 12-231-2 is a fuel injection specific grind, they suggested it to me....I wouldn't have even known about it except for them suggesting it.
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    That's a Comp Xtreme 4x4....it's the same cam I have. I would imagine it'd drive your MAP sensor nuts.

    I've been told keep fuel injected engines in the 112-114* LSA. I can't confirm nor deny that my cam won't work in a TBI engine, but I don't think I'd take any chances.

    It's a GREAT grind though, I'll tell you that. If you're not afraid to take it apart if it doesn't work out, I'd HIGHLY recommend it.

    And tell me how it works out too, I'd just like to know for future reference.
     
  11. solowookie

    solowookie 1/2 ton status

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    I have a computer compat. cam in JMT that has a 110 lobe sep - but crane has done some funky stuff with it so the computers don't have a problem. still if it has lower then a 112 lob sep I'd call them again, and talk to somebody else to verify they aren't full of B.S.
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I agree. MAP sensors don't like overlap.
     
  13. solowookie

    solowookie 1/2 ton status

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    no they don't, but the cam I'm talking about is a crane cam compu cam # 114122 - look it up sometime - 100% computer compatible with 110 lobes. I don't really like the cam though for my app cuz it runs real good, but it has a powerband that really kicks in at 2400 RPM - a little to high for me app (and the RPM range is 1500-4500).
     
  14. ftn96

    ftn96 1/2 ton status

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    Look up the Edelbrock TBI cam PN 3702. Thats what I've decided on for my 90 TBI 350 rebuild. Also call Crower and talk to their TECH's Hell, they'll grind one specifically for you for realitivly cheap!!
     
  15. Charly

    Charly Registered Member

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    I went with the 12-388-4
     
  16. Charly

    Charly Registered Member

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    Ok....I decided to go with the 12-388-4, I met someone with an almost exact same rebuild of the 350 and he uses this cam
     
  17. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I think that's a mistake. The PN 12-249-4 would have most likely given you more torque. The specs, besides lift, are nearly identical.
     
  18. solowookie

    solowookie 1/2 ton status

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    yea, and when I called comp cam's that is the cam they recommended. (talked with 2 different people)
     

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