holley street dominator vs quadrajet

Discussion in 'High Performance Modifications' started by jroach, Sep 10, 2019.

  1. jroach

    jroach Veteran Member

    Messages:
    1,289
    Likes Received:
    4
    Joined:
    Apr 9, 2007
    Location:
    petersburg MI
    for the record I am a big fan of the quadrajet and while im sure there are those much better than myself, I am quite good at tuning them, but im getting frustrated with poor manifold choices and being stuck with adapter plates. does anyone have any experience with the street demon carbs? they look like fairly decent carbs. one thing i don't like is that the metering rods are stepped intstead of tapered. i would be looking at a 750 to match the cfm of my quads. the next carb i need to setup will be going on a big block mopar to replace the feedback thermoquad that is currently on it, if that matters at all.
     
  2. 1980RS

    1980RS Veteran Member

    Messages:
    3,100
    Likes Received:
    481
    Joined:
    Jun 17, 2006
    Location:
    MN
    It's kind of hit or miss with the Demon street carb, some like it some don't. Was the same thing with the 6210 spreadbore Holley. On the street the Holley had way better tuneability but the Q-jet if done right will put most Holley's to shame. If you want a Q-jet that screams try to find a Pontiac one with the dual ring pri. boosters, I hear they are the cats meow in the racing world.
     
  3. biker

    biker Veteran Member

    Messages:
    733
    Likes Received:
    49
    Joined:
    Dec 7, 2014
    Location:
    New Liskeard Ontario Canada
    I have a 750 Street Demon on my 383. Very tuneable (had to buy their tuning kit) and any tuning difficulties were my own fault. Very easy disassembly, good quality construction. I tightened the secondary air door spring to bring the secondaries in more smoothly, leaned the secondary and primary jets, lightened the metering rod springs to work with my lower idle vacuum, and dialed the choke in for my engine.
    Wouldn't mind slightly lighter return springs, but not a priority. Managed to fit a very low air cleaner with minor mod to the cleaner base.
    Before the TKO 600, I was getting 22mpg on the primaries on long trips with a fairly rumpity cam. I'm happy with that.
     
  4. biker

    biker Veteran Member

    Messages:
    733
    Likes Received:
    49
    Joined:
    Dec 7, 2014
    Location:
    New Liskeard Ontario Canada
    I think people who don't like it just may not understand carbs well. It couldn't be more straightforward, and it doesn't have any glaring faults.

    I also love quadrajets, but it's tough to find ones with out warps, air/fuel leaks, or butchered parts. I wanted to start with a new, simple carb and so far I'm impressed.

    The big decider for me was it was cheaper than a quad built by any of the good carb guys you can find online.
     
  5. jroach

    jroach Veteran Member

    Messages:
    1,289
    Likes Received:
    4
    Joined:
    Apr 9, 2007
    Location:
    petersburg MI
    would you say the street demon is as smooth as the qjet? it seems very similar to the edelbrock, which i hear alot of mixed feedback on. im not going for big power on the car this will be going in. mostly looking to get enough out of it that it is safe to merge on a short on ramp, because at probably less than the 200 hp rating and 5000 lbs its not. I have been building most of my quadrajets from swap meet cores, so getting a new carb for less isn't really a factor. i just really like a quadrajet but the manifold selection is garbage for spread bores and when you want to run a higher rise manifold like the eddy rpm that carb adapter can be the difference between fitting under a flat hood or not.
     
  6. 1980RS

    1980RS Veteran Member

    Messages:
    3,100
    Likes Received:
    481
    Joined:
    Jun 17, 2006
    Location:
    MN
    The street Demon is basically a Thermoquad with smaller secondaries. Was a good carb in it's day. Mopar people swear by them in the racing realm.
     
  7. biker

    biker Veteran Member

    Messages:
    733
    Likes Received:
    49
    Joined:
    Dec 7, 2014
    Location:
    New Liskeard Ontario Canada
    It runs every bit as smooth as my beloved quads, my only complaint would be the throttle return spring and the linkage transition from primary to secondary is noticeable in the pedal feel. The small primaries are awesome and the idle and primary tuning are easy and quite efficient.

    I have an edelbrock RPM QJet intake, and my Qjet fit perfect on it. That might be an option for you. I actually had to add a 1/16 plate to it to use the street demon. So, opposite problem from you. The plate is not an adapter, it just seals the fat part of the spread bore secondaries. The street demon will fit your manifold just fine.

    The street demon has little if anything in common with the eddy carbs. I've had a couple of those too.
    Street demon linkage lines right up on my 81, accepts factory clip. Fuel inlet is in totally different location.
     
  8. jroach

    jroach Veteran Member

    Messages:
    1,289
    Likes Received:
    4
    Joined:
    Apr 9, 2007
    Location:
    petersburg MI
    i have never seen a spread bore eddy rpm intake. where did you find that?
     
  9. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

    Messages:
    14,914
    Likes Received:
    425
    Joined:
    Mar 25, 1999
    Location:
    San Jose, CA, USA
    Demons are good carbs, but there are (were) little things that annoyed me about them. Linkage doesn't clear some common air cleaners, nor the Needle screws

    If I was ever going to put up with a carb again, there's only one place I'd go
    https://prosystemsracing.com/street-dragrace/
     
  10. biker

    biker Veteran Member

    Messages:
    733
    Likes Received:
    49
    Joined:
    Dec 7, 2014
    Location:
    New Liskeard Ontario Canada
    Edelbrock still lists the part number I think. I bought mine brand new 3 years ago from a chain parts store in Ontario Canada. It has "RPM QJet" cast right into it, just like the firing order.
    I had no issue with the linkage even with a very low proform ac base. However, I did have to cut and weld the base to clear the choke housing.
    Lowend, what didn't you like about the needle screws? I like them.
    If I don't eventually go with injection, I will hunt around for a new Qjet built by a good performance builder. For now though, I like the street demon. Really works well.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.