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Q-JET Q

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by talldogg, Oct 23, 2000.

  1. talldogg

    talldogg 1/2 ton status

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    Well I'm preparing my 454 to go into the K5, unfortunately I don't have a carb for it. I'm thinking of going with a Quadrajet, I want to avoid aftermarket manufacturers and EFI. I also want to avoid EGR and anything that will add more complication to the install. Any recommendations on what application to get a Q-jet from? I stopped by Auto Zone and rebuilt Q-jets, with warranty are pretty cheap, but they don't have them in stock so I can't look at them before I chose one. Here's some of the applications I have in mind.
    70-76 Caddy with 500 ci
    early 70's Monte Carlo with 454
    early 70's SS Camaro with 454
    early 70's one ton dually
    Does anyone know a link where I can look up the specs (CFM's, electric choke, non-EGR) on the carbs that came on these cars?
    I'm also swapping the intake, what type of bore do I need? Is spread bore the only compatible/recommended for the Q-jet?
    Also, would it be a waste of time to look for a Q-jet in need of a rebuild and rebuild it myself, BTW I've never rebuilt one, so is there a good book/video to help me learn?
    Thanks.[​IMG]

    It's not what you buy, it's what you build!
     
  2. rich'90

    rich'90 1/2 ton status

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    Not sure about the application of q-jet. I got one for my wifes J**p off a camero but hers is the new style heads and intkae manifold. I would caution you on rebuilding the quad yourself. I tried it on my wifes and finally gave up and took it to a friend at the speed shop. I think it is probably the most complicated rebuild. Only my opinion though and I have been accused of being pretty stupid. Who knows, give it a shot. Why are you ruling out TBI? Do they even make it for 454's? TBI works great on my 383.
    Anyway, good luck!

    Go heavy or Go home[​IMG]
     
  3. Most Q-jets are the same cfm, some big block vets had 850 cfms.I would get one for an 82 or so with an electric choke,they're 795 cfm carbs.But if I was'nt going to use an egr I would use the 850 edlebrock version.Just my $.02
    Good Luck

    IF IT AINT BIG IT AINT BAD!!!!!!
     
  4. Andreas

    Andreas 1/2 ton status

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    Yup, q-jets are spreadbore only and usually around 750 cfm. They sat on 350´s too, in the seventies, so there´s a lot of vehicles they can be found on. I got a 4MV (750cfm)myself. Came originally in my 350 equipped Blazer-76 and it´s a good carb, no doubt about that. However, I´m gonna try a Holley 750 when I´m done with my engine (sb406), just to see if I like it [​IMG]

    Andreas

    406cui of pure sh*t[​IMG]
     
  5. Burt4x4

    Burt4x4 3/4 ton status

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    The RochesterQ-Jet 4MV is 750cfm and was used on most non-egr intakes. The EdelBrock 1901 Q-Jet is also 750cfm and non-egr. I have the Edelbrock 1901 on my 350, duno haw it will perform on you 454 but I will assume it would work fine??!!
    Good luck

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    http://www.burt4x4.coloradok5.com
     
  6. talldogg

    talldogg 1/2 ton status

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    Rich,
    I'm avoiding EFI (TBI/TPI) because of the cost, and slightly because of the complexity. Not that I'm affraid, I just want to keep my rig simple. I might take that route with my Camaro in the future, but that's another story.
    BigBad,
    I've seen the Edlebrock carb in Jeg's/Summit and I am considering it, but once again it is a little more dough. The rebuilt Q-jets were under $200 at Auto Zone. I think for half the amount I might want to give them a try.

    It's not what you buy, it's what you build!
     
  7. Jeff427

    Jeff427 1/2 ton status

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    Talldog, I read some where that the Pontiac 455 in the Trans-am had 850 cfm Quadra jets, but I don't remember which year, most other large displacment GM engines had 800 cfm Quadra jets some had 750s. You should be happy with a replacement for 500 Caddy, as long as that is actually what they give you. I know you said you wanted to avoid aftermarket companies, but take a look at this one and see what you think, http://www.jetchip.com/fuel/streetmaster800.cfm. I also have some links to Q-jet info, but I will have to post them later. I need a search tool for my bookmarks.

    Jeff427
    <font color=red>Mud Dog Off Road Club</font color=red>
    http://muddogoffroad.coloradok5.com
     
  8. Jeff427

    Jeff427 1/2 ton status

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  9. talldogg

    talldogg 1/2 ton status

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    Jeff427,
    I really appreciate the help, and I'm sure that it might be usefull to others. Thanks again.[​IMG]

    It's not what you buy, it's what you build!
     
  10. talldogg

    talldogg 1/2 ton status

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    Jeff427,
    I just printed out that link, it's great, thanks a lot. Now I can go into Auto Zone with some part numbers and not look like a dumb a$$.[​IMG]

    It's not what you buy, it's what you build!
     
  11. Wheels

    Wheels 1/2 ton status

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    Rebuilding a Q-Jet is not that complex. Tha hardest part is getting all the metering rods lined up and in their respective spots (they are attached to the top plate). One of the biggest problem with them and for that matter all carb's, is the bottom plate with the butterfly valves. The rods that hold these in the venturi runs out the base plate and wears this area out (steel vs. aluminium). This causes vacuum leaks that can't be fixed easily. On the 454, if it's a mild engine, the 750 to 795 would be more than adequate. The total volume that the carb is rated at is with wide open throttle, and if you arent planning to run this on the strip, I wouldn't worry about the bigger ones.
     

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