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Your humble opinion

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by dmntd, Mar 14, 2005.

  1. dmntd

    dmntd Registered Member

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    I am wanting to replace the quadrajet that is in my 85k5 350. I was thinking of a edelbrock 650 or 700 any input would be appreciated.
     
  2. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    I don't think many on here will tell you to do it. Apparently the e-brock performer carbs are awesome for a street driven vehicle, but have fuel delivery troubles on rough roads and steep grades. I have a performer 600 cfm on my K5 that came with it. The engine would die on washboard roads while I was coasting. I haven't had that problem since I installed the offroad kit, but I havent really done any steep climbs/descents, or gotten off camber with it. I'm looking to get a rebuildable q-jet set up for my motor, a gm crate 350. From what I've read on this site, a q-jet properly tuned for your particular engine is the best way to go, if you are carbe'd.
     
  3. Stoopalini

    Stoopalini 1/2 ton status

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    Check out SMI Carbs.

    I ended up getting a rebuilt quadrajet from them. I'm still in process of putting a new motor in, so I can't tell you how it runs; but after all the research I did on a good carb, and after talking to Sean over at SMI, I purchased one of his stage 2 rochesters.

    Give him a call and tell him what you have for a motor and what you plan to use the truck for. He can build you a custom carb for your application.

    Thomas.
     
  4. dmntd

    dmntd Registered Member

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    Unfortunatly I don't know crap about carbs or fuel systems, but I am willing to work and screw up/learn. The current carb won't enguage 4bbl even if you use your hands and try it manualy. My K5 only sees the pavment not the dirt (for now anyway) and need an interm solution. I hate having that heavy beast with a 350 and only 2bbl working. I have heard quadrajets suck from some people I know but thought I would ask the experts here first. I still don't know what I want to do with this truck. One day I will figure that out :laugh:
     
  5. Stoopalini

    Stoopalini 1/2 ton status

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    Usually, people who say q-jets suck are those who tried to tune one and don't know how. The q-jet can be difficult to rebuild and tune yourself, but a properly built and tuned Q-jet will run awesome! Not only for off roading, but there are many a drag racer who run Q-jets because of the power making capabilities of them. They have relatively small primaries and large secondaries. This makes for decent gas milage when putting around, and good power when you need it.

    If you're looking for a quick cheap bolt on carb, you can probably find a better deal then a quality rebuilt Q-jet. But if you're looking for power, reliability, and off-road capability, I would definitely recommend a quadrajet.

    Thomas.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    So what exactly is wrong with the secondaries?

    Even with the engine roaring away in park/neutral, they aren't going to open. With the engine idling, you'll have a very hard time opening the secondary air valve also, since it is held shut with vacuum on a bunch of Q-jets. I suspect this is the "problem" you are experiencing.

    If you can't physically move the upper throttle blades, (air valve) or the lower ones when the engine is hot, then there is a problem that can probably be fixed pretty easily.

    I've never wired secondaries shut, but I suspect if you have non-functioning secondaries, you'd REALLY know it.
     
  7. MA87K5

    MA87K5 1/2 ton status

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    Try this for the secondaries. Loosen the 4 carb mounting bolts. The carb might be off centered. If it is and the secondaries open after wiggling the loose carb, then open the secondaries all the way and tighten the carb back down with the secondaries open. the secondaries are usually spring loaded. There is a small lever on the opposite side of the throttle lever that prevents the secondaries from opening when it is cold. Move the lever to open the secondaries. Hope this helps.
     
  8. SkulzNBonz

    SkulzNBonz 1/2 ton status

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    As a matter of fact, there is a shop here locally that the old man has been rebuilding Q-Jets for 25+ years. A lot of the locals swear by him (not at him). $162 + tax. I pick mine up in the morning.

    John
     
  9. 1-ton

    1-ton 1/2 ton status Premium Member

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    If you go with a rebuilt Q-Jet, then make damn sure that they re-bushing the primary throttle shaft (many re-builders do not do this). This is the number #1 problem with old, worn out Q-Jets (the primary throttle shafts wear out). I have seen people spend a lot of money on rebuilt Q-Jets, and then still have problems with vacuum leaks through the main throttle shaft, and not idling properly because the main throttle shaft is "cock-eyed" and hanging up.
     
  10. nau81blazer

    nau81blazer 1/2 ton status

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    I wouldn't go with an edelbrock. I have a performer right now and I experience most of the problems these other guys are talking about, plus some. I haven't really been happy with it since the day I got it, i'm just to poor to do anything about it:) .

    --Adam
     
  11. sickquad

    sickquad 1/2 ton status

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    Love my Edelbrock on the road, hate it off road.

    -Chris
     
  12. aduff85k5

    aduff85k5 Registered Member

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    just got a truck avenger carb from holley. now the engine runs like crap. gotta get the engine running up to par. the holley is good for 40 degree incline 30 degree declin and side manuvers.
     
  13. akbound

    akbound 1/2 ton status

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    From what I remember (I loaned out my Haynes Rochester Manual), the secondaries only open under load. Therefore, if all is working well you should feel/hear them open.

    Quadrajets are the way to go and you don't have to pay $350 or more. Just get a rebuilt one. I have had really good luck with the ones from Autozone. The last one I got cost about $120 and I just bolted it on and the truck started right up. Slight mixture adjustment and it was good to go.
     

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