Register now to get rid of these ads!

Quadra Jet - CFM Question

Discussion in 'The Hokey Ass Message Board' started by southerncad, Feb 5, 2012.

  1. southerncad
    Joined: Feb 5, 2008
    Posts: 766

    southerncad
    Member

    :confused: I have a Quadra Jet that was on my Olds 350, will this work on my
    454 BBC that is bone stock. Will it provide enough CFM for the 454?
    This is probably a elementary question...but not for a Carb challenged guy:D
    Thanx in advance for any info.
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 48,340

    squirrel
    Member

    yeah, it should be fine.
     
  3. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    It should if its a 4 barrel,I dont think rochester made a 500 cfm 4 barrel,If its a 2 barrel ,No way
     
  4. XXL__
    Joined: Dec 28, 2009
    Posts: 1,948

    XXL__
    Member

    Qjets are usually 700cfm (there were some 800cfm units on Pontiacs).

    Chevy and GMC big block applications came with Rochester 2bbls all the time. A Rochester 2GV is plenty for all but high speed top end on a bone stock 454.
     

  5. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    I know my 69 olds was a 500 2 barrel ....It probably would work on a big block ,But wheres the fun...............
     
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 48,340

    squirrel
    Member

    huh, the only big block Chevy I've seen factory equipped with a 2bbl is the 1969 265 hp 396 installed in full size cars.
     
  7. Deuces
    Joined: Nov 3, 2009
    Posts: 19,956

    Deuces
    Member
    from Michigan

    Bolt it on and tune the idle mixture screws with a vacuum gauge.... ;)
     
  8. Deuces
    Joined: Nov 3, 2009
    Posts: 19,956

    Deuces
    Member
    from Michigan

    I've seen one on a '68 er '69 Chevelle or Malibu wagon once... I about flipped... :eek:
     
  9. XXL__
    Joined: Dec 28, 2009
    Posts: 1,948

    XXL__
    Member

    Sure, but that's different than saying "no way."

    I had a '77 C-30 with stock 2-bbl, a shop I worked for in high school had 2 366-equipped trucks with 2-bbls, and a friend's dad bought a brand new Chevelle that had one. Perhaps GM was cleaning the parts bins on the car, but the big trucks had published RPO's for that config. Of course, big trucks like their fuel at lower RPM's, so fat primaries are all they need, and the Qjet is all about the secondaries.
     
  10. draggin'GTO
    Joined: Jul 7, 2003
    Posts: 1,766

    draggin'GTO
    Member

    Q-jets come in two flavors.

    750 & 800 cfm.

    Either one will feed a stock 454 just fine.
     
  11. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    I still wouldnt put 500 cfm on a 454 ,,,,,Thats why I said no way,Big blocks I think need a minimum of 600 cfm
     
  12. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,426

    Von Rigg Fink
    Member
    from Garage

    Most Quadra jets are capable of 750 CFM..some Buick and Pontiac versions were capable of around 800 CFM

    Ive seen them on as small a C.I.D. engines of 305 to as lage as 454's

    its possible they could even be used on smaller CID engines and larger than Ive seen ..
    they are unique in the way that they will only give the engine what it calls for due to meetering being done by vaccuum..
    Granted they have to be in good condition ..if not..all bets are off
     
  13. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,101

    David Chandler
    Member

    I have read that GM used 2bbls on some applications like heavy vehicles because there was a concern about having enough vacuum to operate the secondaries in some situations. 400 SBC came with a 2bbl, as did my friends big old Buick nailhead. But dispite the cfm ratings Q jets came on 4.3 V6's where in theory they would be far too big for the engine under most "street" driven applications. The key is the secondary air feed opening, I believe. That way they don't allow more than what the engine can handle. So I see no reason why one would not work on your application, if it was tuned properly. It can certainly flow more than a 2bbl.
     
  14. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    I wish he would chime in and say its a 4 barrel ....Only reason I said about the 2 barrel I had a 69 olds factory 2 barrel carb 350 ....Of couse I put a holley on it....
     
  15. zman
    Joined: Apr 2, 2001
    Posts: 16,593

    zman
    Member
    from Garner, NC

    A Quadra Jet is a 4 barrel.
     
  16. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    I know but but some people call 2 barrels quadra jets ,,,,I know quad means 4 ......
     
  17. ray-jay
    Joined: Feb 23, 2008
    Posts: 200

    ray-jay
    Member
    from Buford GA

    Some Q-jets used on smaller motors had longer stop tabs on the secondary air door. This would keep the air door from fully opening thereby lowering the cfm.
     
  18. zman
    Joined: Apr 2, 2001
    Posts: 16,593

    zman
    Member
    from Garner, NC

    really? wow, I weep for the future of the hobby.
     
  19. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    Ive heard of people referring to them as rochester quadrajet 2 barrels.Had a parts guy that didnt know what points are ,Were in for stupid society ,Yesterday I spent 4 hours at 2 different sams clubs,I was looking for tires,They didnt have the size I wanted,Then they tell me they cant install anything bigger than what the car calls for.In this case it was a truck.Couldnt find 98 had a 99 listing ,So far that was a half hour ,I grabbed 2 tires off the shelf and left,I had a broken belt left side ....Had sears spin and balance them,I do think were in for a stupid society and sorry for the rant.....If its a 4 barrel 600 cfm is plenty ....Big blocks like smaller cfm ,Especially off the line , Street car Top end different story Driver or dragrace ,Many variables .
     
    Last edited: Feb 5, 2012
  20. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,035

    gimpyshotrods
    ALLIANCE MEMBER

    Damn. I just hit my head on my desk.:eek:
     
  21. Da Tinman
    Joined: Dec 29, 2005
    Posts: 4,226

    Da Tinman
    Member

    uh the 2 barrels are Duo-jets, says so right on top......... Duojunks if you've ever tried to fix one.
     
  22. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,049

    Truckedup
    Member

    Some of the last GM Rochester two barrel carbs looked like the front half of a Quadrajet.I suppose some might not not know the difference.
    Lucky for me most Rochester two barrels say "2 Jet or Dual Jet",so I don't have to spend time looking into the carb to count the big holes to know it's not a four barrel..
     
  23. southerncad
    Joined: Feb 5, 2008
    Posts: 766

    southerncad
    Member

    Thanx for the input....and to clarify things for some folks:D Yup, the Quadra Jet I referred to IS a 4 barrel:rolleyes::rolleyes:
     
  24. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    It may have caused some confusion when the early DualJets actually had the same size carb body as the 4 bbls with the secondary air valve area cast over.
     
  25. aerorocket
    Joined: Oct 25, 2007
    Posts: 488

    aerorocket
    Member
    from N.E. P.A.

    Two barrels did come standard on some large autromotive V-8's. The 1970 cuttlass 455 SX turnpike cruiser came with a two barrel carb.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.