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89 tbi intake on 70's 350 heads

Discussion in 'The Garage' started by ProJunkRacing, Jul 19, 2005.

  1. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    who all has done this swap where u drill out the holes anybody explain or got pics i need to put an 89 tbi intake on my 75 350 heads

    thanks phil
     
  2. BiggerRigger

    BiggerRigger Registered Member

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    Are these the stock heads off the blazer? If so its my understanding that you do not have to change any thing. If they are vortex heads than you will have to drill them.
    Aaron
     
  3. btolenti

    btolenti 1/2 ton status

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    I have heard that the two inside holes on each side are slightly bent in on the 87 and up heads.... The older heads had the same two bolts the same as all the others on the intake....straight up and down. Basically, you drill out the middle two holes on both sides of the intake so that you can make it bolt up to the older heads. Then you have to use a washer that will completely cover the hole to you can torque it safely. I would also add some rtv to make sure there are no leaks.... :dunno:
     
  4. Thunder

    Thunder 3/4 ton status

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    Why dont you get a aftermarket manifold and buy a TBI adapter. Putting a TBI manifold on good heads wont do a whole lot of good. They flow like crap.
    Bout all they are good for is making torque.
     
  5. R72K5

    R72K5 Banned

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    tbi one is stock too, you can easily and quickly enlarge the ports runners of the intake/heads, its not hard at all with tapered metal cutting bit and little air drill or evne electric or a higher voltage cordless one

    match the runners of intake and heads together in size and there you go but dont polish them, only polish the exhausts and remove casting bumps and such, but no more than that, it will be quite a bit better you will notice it in certain rpm range

    to bolt tbi intake or heads to carb heads or intake all you have to do is angle grind the four center holes to a little different angle, IE vertical a bit more, is all, aint hard and real quick easy to do,

    gm made factory carb intakes for 87 u heads btw get them from the 87 88 caprices like my 88 brougiham, its tbi heads 305 and rochester q jet factory original, and camaros and firebirds were like this too these years, some anyways, but all the caprices were with 305 anyways


    hope i helped somehow,

    happy swapping :D
     
    Last edited: Jul 21, 2005

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