Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting point?

Discussion in 'The Venerable Q-Jet' started by NickEv, Jan 2, 2015.

  1. NickEv

    NickEv Well-Known Member

    I looked it up and it shows its a 76 unit for a 454 Chevy,but it has a front feed bowl?
    Did Chevy ever use a front feed style carb?
    Any ideas what size it may be and what kind of calibration it came with?
    Any opinions on a starting tune up?
    Its going onto the following combo: IN DENVER COLORADO!!!!!!!!!!

    364" engine
    10.25 compression ratio
    227-234@050 -.600" lift hyd roller
    Heads flow 290 cfm through manifold
    Dual plane ported intake
    3500 stall
    3.73 gear
    3400 pd car street / strip usage
    Thanks
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Attached Files:

  3. NickEv

    NickEv Well-Known Member

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    That's where I saw it was for a Chevy BB
    But I also read where Cliff R said all frt feed mid 70s carbs were 800 cfm ,yet this one looks to be a 750
    Also I thought only BOP car used frt feed fuel bowls???
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    Did you look for the "bump" at 8:00 like in the left picture? That's the tip off of an 800 which you will think a 454 should get. Then again, 70 jets sounds more like a 750 carb. 800's usually get mid 70 jetting.

    I also thought Buick and Olds used the front feed. I guess there is an exception to everything.
     
  5. Cliff R

    Cliff R Well-Known Member

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    Mid 70's Chevy 454 carbs were front inlet, but still smaller cfm and divorced choke. ALL of the front inlet hot air choke models, Buick, Old's or Pontiac will be the larger castings. Most of the side inlet Chevy auto carbs from 75-up are also the larger castings, but they made quite a few smaller ones until 1980.

    The carb in question here is a big block carb, large MAB, and emission calibrated. This is an advantage for the high altitude application. It also has APT in the baseplate, if you can get the screw removed, an external APT screw can be added for fine control of the part throttle A/F without taking the carb apart.

    The carb will need a jet and rod change for what you are doing, and minor modifications to the idle system, but its a good choice for the application, providing you can use the factory divorced choke set-up.....Cliff
     

    Attached Files:

  6. NickEv

    NickEv Well-Known Member

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    I looked on the website but they arent shown?
    Do you stock these screws?
    Any other required modificaion needed to run external screw?
    Thanks
     
  7. carmantx

    carmantx Never Surrender

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    The original apt screw has to be removed from the base plate, which can be a tough job. The new adjustable Apt screw then goes in the same threads. I don't do this on all my builds, but I do have the supplies on hand. The quadrajet I run on my car has this adjustable apt in base plate.
     
  8. NickEv

    NickEv Well-Known Member

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    Well there you have it !
    Thanks sir!!!
     
  9. Cliff R

    Cliff R Well-Known Member

    Re: Qjet 17056212 with front fuel feed-what cfm and manufacture is it? Starting poi

    Those type APT screws can be difficult to remove. Some come right out, others will require heat, plenty of penetrating oil and patience. We install the external APT on most of the carbs that we do, the only ones that don't get it are the very few that we can't get out of the baseplate.

    Its a great feature, and makes for easy fine tuning on the engine without taking anything apart.

    There are a lot of items that we sell that are not listed on the website......Cliff
     

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