Register now to get rid of these ads!

Max CFM for a 283 SBC?

Discussion in 'The Hokey Ass Message Board' started by poboyross, Jan 19, 2010.

  1. Tudor
    Joined: Aug 20, 2003
    Posts: 6,911

    Tudor
    Member
    from GA

  2. Fenders
    Joined: Sep 8, 2007
    Posts: 3,921

    Fenders
    Member

    For the youngsters on here, you might have to explain just what a sash weight is.
    (At my age, I know....)
     
  3. strawberry
    Joined: Sep 13, 2008
    Posts: 291

    strawberry
    Member

    well this thread was a little help thanks
     
  4. poboyross
    Joined: Apr 29, 2009
    Posts: 2,142

    poboyross
    Member
    from West TN


    HAAAA....amen, brother. I started this thread forever ago and it continues to hobble down the dirt road, veering this way and that, but never really answering the original question in depth.

    I have since installed the 500 cfm Carter and it started well and ran nice once I adjusted the idle to about 500rpm. Then, smoke out from behind the external voltage regulator and KERPUT!......will sputter on start and quickly die. Have no idea if it's the regulator or the carb...considering buying new ones of both. EXCEPT this time I'm thinking of getting a 390cfm 4bbl. Guy at the rod shop said that for a bone stock engine you can multiply the cubic inches by 1.25 as a general rule for CFM on your carb. Have no idea if that's legit.
     
  5. This is my new favorite thread... I decided to make it something special.:)

    [​IMG]
     

    Attached Files:

  6. poboyross
    Joined: Apr 29, 2009
    Posts: 2,142

    poboyross
    Member
    from West TN


    That's halfway between dumb and ass.
     
  7. OldSub
    Joined: Aug 27, 2003
    Posts: 1,063

    OldSub
    Member Emeritus

    Years ago I ran a small Holley on a 283. I was told it was about 450 CFM from some Ford. Today I have no idea how accurate that might be. This was a mild '62 motor with Power Pack heads and a used cam and lifters an older buddy said would be perfect as he sold it to me. The motor was an inframe ring and and rod refresh and ran pretty nice. It was my first high school rebuild done in my parents garage over a weekend.

    In a '62 Impala with an cast iron PG it would pace the car I replaced it with up to about 45 mph. I thought that pretty impressive since the replacement car was a '65 Impala with a 396 and another PG. Once it was rolling the big block car was much faster, but it wasn't any quicker off the line. Don't ask about gear ratios or tires, I just don't remember.

    So these memories are all more than 30 years ago and if I measured things at the time I've kept no records. I ran that same 283 in three different cars and was always very happy with it and the small carb worked well for me in what was always really more driver than racer. I sold it when I decided to go to college and have long regretted the sale if not the college.

    I'm NOT a carb expert and don't wish to engage in that dialog here. I do feel that carb, intake and value size all affect (and cam profile) intake velocities and that at street speeds crisp response is more about intake velocity than size. If I were choosing a carb for a 283 today I'm sure I'd be thinking street motor otherwise I'd be building much bigger, and therefore my choice would be all about intake velocity.

    If I could remember exactly what it was, I'd probably choose the same carb, intake, cam and heads I had back then... But that may be more nostalgia than logic.
     
  8. fridaynitedrags
    Joined: Apr 17, 2009
    Posts: 402

    fridaynitedrags
    Member

    Thank you for this post Don, I've been crusading against this stupidity for decades.
     

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.