How much power would this combo make?

Discussion in 'Engine Topic' started by TDPalmer, Mar 8, 2013.

  1. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

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    I keep messing around with different options for replacing the old tired smoking engine in my Camaro. I was seeing about rebuilding a old 350 I have laying around into a roller engine with vortec heads. The crank in the 350 is still good and would not need to be replaced. I'm wondering if I have everything here minus the carb & accessories like the mechanical fuel pump, harmonic balancer, pulleys, brackets etc that I can swap or reuse.

    The items I have in my Summit cart are:
    (2) Assembled Summit Racing® Vortec Cylinder Heads SUM-151124

    (1) Summit Racing Street & Strip® Stage 1 Intake Manifolds SUM-226018

    (1) Summit Racing® Chevy 350 Engine Kits SUM-SBCKIT1-300 with .30 over rings and flat top pistons, with stock rod bearing undersize, and stock main bearing oversize.

    (1) COMP Cams 26918-16 - COMP Cams Valve Springs

    (1) COMP Cams Thumpr Hydraulic Roller Cam and Lifter Kits (Duration 291/311, Lift .522/.509)

    (1) Proform GM Licensed Chevy Small Block Engine Dress Up Kits Tall Valve Covers (I'm going to ask Summit about swapping for centerbolt valve covers)

    Would all these parts work together and am I forgetting anything major? Summit told me a while ago that I can use the factory stall converter with the Thumpr cam. The assembled Vortec heads have a max lift of .520 and the Thumpr cam has a max lift of .522 would I have to change valve springs?

    Around much horsepower would this make?

    Thanks!
     
    Last edited: Mar 9, 2013
  2. Brett350

    Brett350 Veteran Member

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    a solid 400hp, maybe more.
     
  3. luda

    luda Veteran Member

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    Any difference in the Summit Vortecs and stock Vortecs in terms of exhaust flow? If not, wouldn't one want a little more lift on the exhaust side than the intake to get the most out of the cam?
     
  4. wild84

    wild84 Veteran Member

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    No. Cam is to big. Springs are only good to .520, cam is bigger then that with factory ratio.with 1.6, it'll be worse.
     
  5. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    Oh god the thumprs. I just took the big motha thumpr out of my neighbor's car after making fun of him for about 2 years, replaced it with a comp 280HR. You shouldn't be using a stock converter with any aftermarket cam, just because it will work does not mean it will work well.

    Those summit vortecs are not real vortecs, you can tell from the shape of the intake ports that it is a Dart "vortec" head and they use a Gen 1 port, which kind of misses some of the benefit of a vortec head. I think those use a vortec chamber but gen 1 ports, it's kind of a hybrid head.

    And yeah if you put together the combo you made above with 1.6 rockers plus that cam you would crash the valvetrain as soon as you cranked it up. 1.6 rockers have no place on a build like that.
     
    Last edited: Mar 9, 2013
  6. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

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    I wasn't quite sure what larger rockers do, I just know everyone talks about having them :screwup:. What's the difference between the Summit Vortec Heads and actual ones? They require a Vortec intake and the intake ports look like all the other Vortec intakes.

    I got rid of the rockers. Added these springs:
    COMP Cams Valve Springs
     
  7. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    Last edited: Mar 9, 2013
  8. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

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    Awesome thanks for the links.

    In the second link this guy was talking about porting these 305 heads, I got these on my car now with no modifications, I think they're 416 or 418 shoot if I could port them and keep my old intake and save money and be just as good as stock vortecs then I'd be a happy camper. But then again I don't know if I'd trust a machine shop around here to do it right.

    I'm still reading through all the bickering.
     
    Last edited: Mar 9, 2013
  9. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    I have messed with home-porting the 416 heads before, it would take a pretty skilled hand to make them even equivalent to a stock 062/906 vortec head, and the cost just wouldn't be even remotely worth it. I would buy the $309/each real GM performance vortecs Jegs has before I messed with old 305 heads.
     
  10. wild84

    wild84 Veteran Member

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    The 1.6 rockers add lift (turns your .522/.509 cam into a .557/.542) and duration (don't know the math on that one though). Also, I'd rethink the thumpr cams. They were designed to be a "look at my car, it has a lope, it's cool!!" though every other hotrodder thinks your a douche. There are much better designed cams that work better for what your doing/
     

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