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Quick question

Discussion in 'The Garage' started by bleedchevy, Nov 4, 2003.

  1. bleedchevy

    bleedchevy Registered Member

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    Will an tbi intake from an 1988 350 bolt up to a 1986 350? I know about the differences in cams and such, thats already been tookin care of. /forums/images/graemlins/cool.gif /forums/images/graemlins/k5.gif.
     
  2. Confedneck

    Confedneck 3/4 ton status

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    are they both vortec motors?
     
  3. sled_dog

    sled_dog 1 ton status

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    if the heads from the 88 were put on the 86 yes, otherwise I doubt it. Stock intake won't bolt onto the stock heads on the 86. 88 has the 4 bolt straight down intake bolts.
     
  4. bleedchevy

    bleedchevy Registered Member

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    There both standard 350s with stock heads. except for the cam.
     
  5. bleedchevy

    bleedchevy Registered Member

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    Thanks guys, means a lot. /forums/images/graemlins/thumb.gif
     
  6. heavy4x4

    heavy4x4 1/2 ton status

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    Neither of these years are vortec motors, guys. (That doesn't make a difference at all, actually...it matters if they have vortec heads because those use the different intake bolt pattern). /forums/images/graemlins/thinking.gifAs far as I know, the bolt pattern for the TBI intake is the same as the carb intake.

    EDIT: My mistake...sorry. I did some quick checking and the heads on the '88 have the 4 inner bolts at an angle of 72 degrees instead of the 90 degrees of the '86. So, with slight modification you can make your '88 intake work on the '86 heads. Or, just use the '88 heads (if they're not junk) on the '86 block.
     
  7. bleedchevy

    bleedchevy Registered Member

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    I hope they will, i only have a week to do the swap and break in the motor before i go back 500 miles to school.

    Well, then how can i modifiy the intake to work?
     
  8. heavy4x4

    heavy4x4 1/2 ton status

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    To make your '88 intake work on the '86 heads, you'd need to machine the inner 4 holes. The spacing and size is the same...just the angle of the bolt is different. I believe what you'd need to do is make the surface of the intake manifold where the bolt head sits perpendicular to the angle that the new bolt makes...you'd also need to drill the holes in the intake to match the new angle the bolt has to go in at. I'm not positive with all that, though...never done it, so maybe someone will speak up who has.
     
  9. blasterD

    blasterD 1/2 ton status

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    I would use the '88 heads along with the tbi manifold. That way everything will be bolt on and you will bump your compression up a little. The '88 350 heads had a 60cc chamber while the 86 heads should have a 76cc chamber.
     
  10. Hossbaby50

    Hossbaby50 3/4 ton status

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    If the 88 heads are good swap them too. I just got done opening the holes on a 88 TPI intake to fit on an 85 motor. You better be ready to do alot of opening and test fitting. It would have been alot easier to swap heads, but I didn't have a set laying around or money for a new set so I opened the holes up. I spent over 4 hours getting it right. PITA.

    Harley
     
  11. bleedchevy

    bleedchevy Registered Member

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    the heads on the 88 are not in the best shape, the valves need to be regind, seals and springs need to be replaced.
     
  12. Hossbaby50

    Hossbaby50 3/4 ton status

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    It took me over 4 hrs to grind out the holes with the air grinder and drill bit. I had to test fit the manifold no less then 6 times, and I used at least 6-8 tanks of air. I have a 30 gallon tank and my regulators were set to 60 PSI to help slow the air usage of the air grinder.

    If you don't have access to an airtank and grinder then you could probably do it with a drill if you are pretty handy, but it is going to be a PITA either way. A dremel tool would work too, but I don't know how long a bit would last on it. You could probably use a drill bit the same size of a dremel shank to open the holes, but any way you look at it it is going to be a PITA. I have seen a jig that Edelbrock sells which might be well worth the money for the time and hassle saved. Or you could probably take the manifold down to a machine shop that does heads and have them machine the 4 holes for you. If I had it to do over that is what I would do.
     
  13. bleedchevy

    bleedchevy Registered Member

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    i found that holly performance makes an adapter. /forums/images/graemlins/thumb.gif
     
  14. R72K5

    R72K5 Banned

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    vortec started in 85, but isnt the sdame as FI vortec, was just a name before FI vortec came out as we know it now on the later trucks, its just a name just liek hi torque and turbo fire was back in the 60s, but had to do with ratings of the engines


    you can put a tbi intake on carb heads but the center bolts are different angle though, you can fix with dremel, re-angle the holes in intake and then you would be good to go, but not everyone says its ok, but it will work, bolt pattern and everything else is same 55-up sbc stuff
     

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