850 Thermoquad worth the effort?

Discussion in 'Fuel and Air Systems' started by gzig5, Sep 3, 2018.

  1. gzig5

    gzig5 Well-Known Member

    Messages:
    82
    Likes Received:
    27
    Joined:
    May 3, 2018
    Location:
    Mequon, WI
    Local Time:
    9:18 AM
    An acquaintance has an 850 Thermoquad Competition Series #4846 that is still new in the box that he'll let me have for cheap. He has no use for it and isn't into selling stuff on the net. Would this carb be worth the effort to try on my 70 340? I know that rebuild kits are available but the tuning parts seem to be hard to come by? My understanding is that the TQ can be a great carb but tuning is a bit different than a Holley. Car currently has a Holley 650 DP on it. Seems OK after I rebuilt it but I've only got 35 miles on it since I got it running and the trans is slipping so I haven't been able to give it a good workout. Currently has J-heads, LD4B intake and as far as I can tell a relatively stock cam. Will be getting new heads (new TF, W2, or ??), RPM air gap, and as hot a solid lifter cam as I can comfortably run on the street. I have the room under the hood to run a 1" adapter.
     
    Last edited: Sep 4, 2018
  2. CudaJunction

    CudaJunction Well-Known Member

    Messages:
    838
    Likes Received:
    62
    Joined:
    Apr 18, 2010
    Location:
    Oregon
    Local Time:
    7:18 AM
    Holley dp will always run better in the long run. TQs run good but you have to be a carb tuner.
     
  3. yellow rose

    yellow rose Doctor of Thinkology.

    Messages:
    15,297
    Likes Received:
    11870
    Joined:
    Jun 19, 2015
    Location:
    Living on the razors edge
    Local Time:
    7:18 AM
    If you don't want that carb hook me up with your buddy. I'll buy that thing in a New York second.

    I'm serious.

    Let me know.
     
    • Agree Agree x 1
    • rumblefish360

      rumblefish360 so close yet so far away

      Messages:
      31,936
      Likes Received:
      4238
      Joined:
      Jun 21, 2005
      Location:
      New York, on a Island
      View My Photos
      Local Time:
      10:18 AM
      Looks like this?
      It tunes with the first year TQ parts. Very hard to find. It is a little different the regular TQ’s.
      TQ’s can be tricky until you learn them and get used to them. There not as tunable as a Holley. These are a race carb. It is not a standard run of the mill production TQ for starters, the primary only has one booster ring which Leeds to the possibility of a rougher ie and a reduced throttle response when compared to a OEM unit. Also there metering of fuel is different. One solid fuel, the other not.

      I don’t want to start a bidding war with YR, but I’m prepared....
      LMAO
      :lol:
      I’d personally LOVE a second one.

      I LIKE the TQ a lot. Standard car production units work really well for a street or street strip machine. I’d only campaign one if I got paid to do so. The Holley is just way way way more tuneable. For sure, I will run one in the street. IMO, there really quit at home in ether places.
      A4E47FB8-22AC-4544-995E-96EBADCF178A.jpeg 1C31E46D-B3CE-45B7-B832-F0E91B44E73F.jpeg B1CC7C60-53DF-4114-92A5-51E8C9305797.jpeg
       
      Last edited: Sep 4, 2018
      • Agree Agree x 1
      • pishta

        pishta I know I'm right....

        Messages:
        12,738
        Likes Received:
        2630
        Joined:
        Oct 13, 2004
        Location:
        Tustin, CA
        View My Photos
        Local Time:
        7:18 AM
        Not if you don't know how to tune them. Guys who tune them like them, guys who don't hate them.
         
        • Agree Agree x 1
        • cuda620

          cuda620 Well-Known Member

          Messages:
          1,450
          Likes Received:
          127
          Joined:
          Oct 26, 2014
          Location:
          indiana
          Local Time:
          9:18 AM
          I’ll buy it too if you don’t. Correct you gotta know how to tune em. A child can tune a Holley, but it’s never right. Imo.
           
        • rumblefish360

          rumblefish360 so close yet so far away

          Messages:
          31,936
          Likes Received:
          4238
          Joined:
          Jun 21, 2005
          Location:
          New York, on a Island
          View My Photos
          Local Time:
          10:18 AM
          That is because you need more time & experience with them.