Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Carb Gurus - Need help!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by IndianaK2500, Feb 12, 2002.

  1. IndianaK2500

    IndianaK2500 Newbie

    Joined:
    Feb 12, 2002
    Posts:
    3
    Likes Received:
    0
    Ok, first post, a question. And yes, I did search. :D

    Anyway, I just bought a 1983 GMC 3/4 ton 4x4 (350, 700R4)last week, and the carb is giving me fits! First thing, it's missing ALOT of parts, there are several "rods" that are missing, etc, etc.

    So, I'm thinking that I have one of two options. First, I can go to a junkyard and find another q-jet to put on it, and hope it's "ok". The second, is to purchase a Holley Spreadbore replacement, and go with that. (This isn't for offroad, I have another vehicle for offroad, this is my "towrig")

    So, basically I'm looking for something that's gonna give me good performance while towing, and won't give me fits.

    Any suggestions?
     
  2. IndianaK2500

    IndianaK2500 Newbie

    Joined:
    Feb 12, 2002
    Posts:
    3
    Likes Received:
    0
    Oh, yea.

    This thing isn't "computer controlled" is it? I'm looking at different carbs and some mention computer controlled Q-jets.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Not computer controlled in '83.

    There is a third option, which is get a QJ that needs rebuilt (a core if you will) and make one good carb out of two. the rebuild kit is less than $20 9or should be) and if one of the two is good, you won't have problems with the primary throttle shaft needing to be bushed.

    Core QJ should run you about $5. I've got some parts, as others on here do as well I'm sure, so check out www.dorianyeager.com/index2.html
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  4. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Don't get a holly...they suck.
    Me I would be getting the junkyard carb or finding a used carb in the for sale board. If your willing to throw some coin at the deal get the new Quad from Edlebrock. It's a real Quad and it is new and it should bolt on and not need much else. Get the one with electric choke.

    Women dig dents and flat paint!
    coloradok5.com/gallery/Grim
    75 Jimmy, Dollar
    Grim-Reaper
     
  5. IndianaK2500

    IndianaK2500 Newbie

    Joined:
    Feb 12, 2002
    Posts:
    3
    Likes Received:
    0
    Dorian, thanks for the info.

    Actually, what I did was not too far off. I put a manual choke on it, that seemed easiest and cheapest. I also fixed the "Low idle" too, so that's good. I think I'm about 95%.

    So, now I have another Q. On the passenger side of the carb, there seems to be a vaccuum for the secondaries. Now, I believe that there should be a rod that goes from that vacuum, up to a "lever" on the secondaries to open them up? Is that what it is? I looked on your diagram's, and it would seem to be #58 or #322. But, more like 322, going from 320, up to where #58 attaches?

    Seems kind of F----d up, if you know what I mean. I also started tearing off the emissions control stuff, and it still seemed to run ok, so that's cool!

    Thanks again!
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Do you have both of the "vacuum cannisters", like in that pic? 322 is for the choke operation, which CAN affect the secondaries, and 58 is for the secondary air valve.

    The secondaries are held SHUT with vacuum actually, when vacuum drops, (and choke is off) the vacuum relaxes tension on those rods, allowing the secondary air valve ("upper rear butterflies") to open. Incoming air holds it open.

    Missing that upper rod will only allow the secondaries to open without regard to engine vacuum, (kind of) but that can cause problems, with the air valve slamming open and shut, depending on spring tension in the air valve spring. It basically acts as a cushion, but it *might* hurt MPG, but nothing else really.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     

Share This Page