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School me on Intake Manifolds

Discussion in 'The Garage' started by mtnman210, Apr 15, 2006.

  1. mtnman210

    mtnman210 1/2 ton status

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    I really need to get this crappy Holley carb off my truck and go back to the Rochester Quadrajet. Except I've run into a problem, it won't fit on my current manifold because I have vortec heads so I have the weird bolt pattern. I don't really want to run the adapter plate to fit the quadrajet so as long as I'm under the hood I figure I'd look to get some more out of the motor and get a new manifold too. It's going on a slightly built 350 thats mostly a DD but still sees alot of mud and desert. I'd like to keep the torque and horsepower ranges about where they are. It's got some good low end grunt but can still go down the highway at 80. I'm not worried about gas mileage. Ok so where should I start looking? and what types/companies/styles should I be looking at?
     
  2. kgblazerfive

    kgblazerfive keymaster Premium Member GMOTM Winner

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    Performer RPM or Victor JR don't waste your time with any other.
     
  3. Dr. Morgenstern

    Dr. Morgenstern Registered Member

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  4. Dr. Morgenstern

    Dr. Morgenstern Registered Member

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    I couldn't find anything but a regular performer for a spreadbore.
     
  5. littlejimmythatcould

    littlejimmythatcould 1/2 ton status

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    Maybe an adapter plate.... plus it would act as a carb spacer, maybe pick a few extra pounds of torque. Depends on your clearance between your hood and you air cleaner though. Just an idea.
    P.S. I'm running a regular performer intake.
     
  6. sled_dog

    sled_dog 1 ton status

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  7. eagle mark

    eagle mark 1/2 ton status

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  8. littlejimmythatcould

    littlejimmythatcould 1/2 ton status

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    Sorry to get off track, but how much does that set up run? Just curious....
     
  9. mtnman210

    mtnman210 1/2 ton status

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    definitly not off track....that kind of setup would be SWEET! I'm kinda curious on the price for it too. I just don't see it happening for my truck any time soon:wink1:
     
  10. mtnman210

    mtnman210 1/2 ton status

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    a couple quick basic questions:

    whats the difference between single and dual plane?

    and is the quadrajet square or spread bore?
     
  11. sled_dog

    sled_dog 1 ton status

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    quadrajet is Spread bore. The large secondaries "spread" from the little primaries, thus the intake has a funky little look to it.

    Single plane intakes, are just that. There is one single plane that air/fuel enter and travel through. This means that all 4 barrels on the carb are feeding, all 8 cylinders of the engine. Sure this sounds like the best thing for everybody, but it is not. Single planes are meant for more upper RPM flow. They aren't great for low end grunt(though I Have seen some dynos where torque was actually gained with a single plane, that was an exception, not the rule). Single planes are usually taller and make for a straighter shot to the intake ports/valves.

    Dual plane intakes have 2 planes for air/fuel to travel in. One half of the carb(one primary, and one secondary) feed 4 cylinders, and the other half feed the other four. Generally the left side barrels feed the right side of the engine and vice versa. These have more texture to the intake runners and help to atomize fuel better at low RPM. This makes for more torque on the bottom. Now Edelbrock Performer RPMs, have a slight notch in the plenum divider(the part that divides the intake into a dual plane). This allows for air/fuel to travel be fed from all 4 barrels to all 8 cylinders, but not a lot. This is one of the things that makes it a better mid range intake. Personally I just think it better rounded for all applications.

    Now if this is a Port fuel injection system, throw this crap out the window. Port fuel injection(like the one previouslly pictured) or a TPI setup, should be single plane intakes all the time. There is no reason to try and atomize the intake charge when all it is is air and not fuel(we call this a "dry" intake). The atomization takes place, both out of the injector, in the intake port, and into the head chamber(like Vortec heads). Thats another topic but figured I'd note it.
     
  12. mtnman210

    mtnman210 1/2 ton status

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    thanks for that explanation. just what I needed to know
     
  13. eagle mark

    eagle mark 1/2 ton status

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  14. Moody

    Moody 1/2 ton status

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    You could run this intake...it's a Weiand action plus dual plane made for vortec heads. It cost me about 145.00 through Summit with free shipping which is about 40 less than the performer. Nothing against edelbrock I just wanted to use something different and wasn't comfortable using one of the crosswind knock-offs on ebay. It's set up for a squarebore carb and good from off-idle to 6000. If I end up using a Q-jet I'll use an adaptor.

    intake_640x480.jpg
     
  15. R77K10

    R77K10 Banned

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    i dont see the big deal here why doesnt he just get a stock 87-89 caprice impala 4 bbl intake and run it ?
    they are spreadbore aluminum GM
    exact same as all the other car 4 bbl manifolds except the four middle bolt holes are the TBI angle




    lots were carb still and some camaros and firebirds too 87-up

    and some other vehicles

    thats what i would do...
     
  16. sled_dog

    sled_dog 1 ton status

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    My 383 started life as an 89 Caprice 350. It had a steel QJet intake with the TBI angle bolts...
     
  17. Quackaddict

    Quackaddict 1/2 ton status

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    hope this is on topic. The adapter for the manifold. The Q-jet and truck avenger are spread bore. The adapter I got came with 2 plates for use in the adapter. One has 4 holes like the spread bore and one was open like a square bore. The instructions said use the open one for adapting a spread bore carb to an intake like the one pictured does this sound right?
     
  18. beater_k20

    beater_k20 Banned

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    wont work. look at his initial post. he has Vortecs.
     
  19. Chevy305

    Chevy305 6 Lug 14bsf Status Premium Member GMOTM Winner

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  20. mtnman210

    mtnman210 1/2 ton status

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    those are the things making it difficult. I've only found the standard "The Performer" with spread bore and fitting vortec heads.

    I looked at some adapters just for kicks and the only one I can find that fits a spread bore carb to a square bore manifold is single plane...my current manifold is dual. So it looks like the adapter idea is out. Unless--can I run the adapter on the dual plane even though it's for a single plane
     

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