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New 670CFM Throttle Body won't work with TB spacer, what to do???

Discussion in 'The Garage' started by dawson444, Feb 28, 2004.

  1. dawson444

    dawson444 1/2 ton status

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    New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    I just bought a Holley 670CFM TB. I have a TB spacer on my truck. The flaps on the new TB are too big and won't open b/c the holes in the spacer are too small. What should I do? It also won't work when I put it right on the manifold for the same reason. Any ideas?
     
  2. jeffro

    jeffro 1/2 ton status

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    Re: New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    It's supposed to come with a real thick gasket with chamfered holes for the flaps.
     
  3. HarryH3

    HarryH3 1 ton status Author

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    Re: New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    As you've found, the throttle bores on the Holley throttle body are larger in diameter than the stock TBI. Your easiest fix would be to have the spacer tapered a bit so that the throttle blades will clear it, while providing a nice tapered shot into the intake manifold. To take full advantage of the larger bores though, you need to remove the intake manifold and have it bored out larger. /forums/images/graemlins/frown.gif Of course, that assumes that your engine actually needs the additional airflow. With ported heads and more cam you would most likely notice the difference. But with a stock engine there probably isn't much advantage to having more airflow available.
     
  4. dawson444

    dawson444 1/2 ton status

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    Re: New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    I have a 355 (330HP and 380ft/lbs). I am going to have a custom chip made for it. This TB also has 85# injectors. Which would be my best bet? Should I
    1. Try to get that gasket from holley?
    2. Get my TB spacer tapered and leave intake alone?
    3. Get my TB spacer completely bored out and leave intake alone?
    4. Get my intake bored out as well as the spacer tapered or bored out?

    Anything else? I really really don't want to take that intake off, but I will if I have to. What do you guys thing I should do? Thanks!
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Re: New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    If you really want to take advantage of that 670 CFM throttle body then the only option is:
    [ QUOTE ]
    4. Get my intake bored out as well as the spacer bored out?

    [/ QUOTE ]
    Bolting a 670 CFM throttle body onto a pair of holes that are sized for 500 CFM is gonna really limit what the engine can do at the top end. /forums/images/graemlins/frown.gif
     
  6. 88Silverado

    88Silverado 1/2 ton status

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    Re: New 670CFM Throttle Body won\'t work with TB spacer, what to do???

    Get a 4BBl Performer Manifold (Non TBI type) and the Throttle body to 4BBL manifold adaptor from TurboCity. You will have a good manifold that will allow the 670CFM TBI work like its suppose to and be done with it /forums/images/graemlins/waytogo.gif
     

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