Register now to get rid of these ads!

Hot Rods Carb Spacer Advice

Discussion in 'The Hokey Ass Message Board' started by jimmy52dodge, Jun 2, 2017.

  1. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

    Hey Guys,

    I have a stock rebuilt chevy 350 with cast iron quadrajet 4-barrel intake. I plan to install a Demon 625 carb. I know it needs a spacer but I'm not sure which one to use. Does anyone have any advice on the spacer or can provide a spacer part number that will work for me??

    Thanks in advance. Jim
     
  2. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    do it right and save the tuning /drivability troubles and buy the manifold that fits it .
     
  3. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

    They are both spread bore patterns, just need a little clearance to gain full throttle capabilities. I dont believe a new manifold is needed. Spacers appear to be used in many applications without issue.
     
  4. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member


  5. saltflats
    Joined: Aug 14, 2007
    Posts: 12,592

    saltflats
    Member
    from Missouri

    Show some pictures of what you have.
    Not sure what your problem is if they are both spread bore?
     
  6. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

  7. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    If they are both spread bores that adaptor won't work. You may only need one of the 1/4" thick factory GM base gaskets.

    Sent from my Moto G Play using The H.A.M.B. mobile app
     
  8. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

    The demon is a square bore....I mis-spoke earlier. Thanks.
     
  9. Why do you want that carb?
     
    Montana1 likes this.
  10. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

    I had a feeling this question would come up. I maintained the quadrajet cast intake in case the Demon 625 does not work out and I needed to go back to the quadrajet. In general, I chose the Demon 625 because of its simplicity in design, easy aspects to tune, and mainly positive reviews. The quadrajet and edelbrock seem to have their own issues; edelbrock with overfueling, quadrajet with tuning difficulties. Right out of the box, the Demon has great feedback with smooth throttle response, etc; just what I am looking for in a mild driver.
     
  11. flatheadpete
    Joined: Oct 29, 2003
    Posts: 10,478

    flatheadpete
    Member
    from Burton, MI

    I ran a Demon on an AMC straight 6. Damn fine carb. Did take some tuning but once it was there...HOLD ON! I also gave one (a 625) to a friend with a 383 stroker SBC in a monster truck K5 Blazer and it runs really well.
     
  12. jimmy52dodge
    Joined: Aug 12, 2012
    Posts: 9

    jimmy52dodge
    Member

    Thanks for the reassurance flatheadpete. I drove an AMC 258 CID in high school that sounds like it would have benefitted greatly with the demon. It was a great car (my first one), but I was just happy it went from A to B.
     
  13. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    jimmy52dodge wrote -
    ""edelbrock with overfueling,""

    What the hell is..."over fueling" ?

    I read that as, "I don't know how to tune"..!
    I've run many Edelbrock/Carter carburetors over the years with zero problems. Pretty simple devices actually. Even the semi-hated Holley. What the hell, they are just simple (after the initial design) pieces of (mostly) non-moving parts. They can go many years without having to mess with them when set up properly.

    Mike
     
    greybeard360 likes this.
  14. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    The Eddie's are actually easier to tune. So if you have to tune anyway..... Just saying.

    I have never been impressed with the Demons. Maybe that is why they went out of business. Not because I wasn't impressed with them... They just weren't that great.

    Sent from my Moto G Play using The H.A.M.B. mobile app
     
  15. upspirate
    Joined: Apr 15, 2012
    Posts: 2,299

    upspirate
    Member

    They went out of business? I just looked online and they are being sold everywhere.
    Am I missing something?
    (Don't care, just wondering )
     
  16. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    My bad.... Was thinking of a different company. Barry Grant.

    Sent from my Moto G Play using The H.A.M.B. mobile app
     
    Last edited: Jun 3, 2017
    upspirate likes this.
  17. Paint_Rep
    Joined: Feb 10, 2017
    Posts: 77

    Paint_Rep

    Barry Grant and Demon are the same company/carb. They were serious enough of a player for Holley to buy them out last year. I've ran the the new electric choke Street Demon (Thermoquad knock off) on two motors now. Both 290 horse 350 GM crate motors. They are 625 cfm. They run terrific. One was on an Edelbrock Performer intake and it fit perfect. (Obviously it's dual bolt pattern). I also put one on a stock aluminum Q-Jet intake and the throttle blades hit. I had to swap intakes. These Street demons are the closest things to EFI out of the box as far as reliable starting and zero bogs/stumbles. I live in the Midwest so cold starts are a must. The ONLY negative of these carbs after 3 years is that they are a hair on the fat side out of the box. They make tuning kits and I hear they respond amazing on the mileage end, but I've just not gotten around to taking it apart. Hope this helps?


    Sent from my iPhone using H.A.M.B.
     
  18. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377

    indyjps
    Member

    Ive never run a demon, the edelbrocks Ive run are pretty spot on out of the box for a stock /mild engine. They sell a performance and fuel economy version, be sure to choose correctly. Choke kits are readily available. Never needed one.

    A well tuned quadrajet is a very good carb for daily driving.

    Its worth the trouble to change to an aftermarket intake, edelbrock performer has been in production for a long time for good reason - it works, the cast iron stock q jet intakes give up a lot of performanve in comparison.

    If youre set on using a spacer let us know how it works out.
     

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.