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Technical 348 Chevy crank question

Discussion in 'Traditional Hot Rods' started by Coreguys, Oct 8, 2020.

  1. Coreguys
    Joined: Aug 20, 2014
    Posts: 11

    Coreguys
    Member

    Hey there, who knows the why-fore of 348 Chev crankshaft flanges being different? Is it a car vs truck thing, or maybe a year thing? One has a notch, one is solid round. Just trying to figure out if there is any significant meaning to this or not. (hopefully my pic will load)
     

    Attached Files:

  2. saltflats
    Joined: Aug 14, 2007
    Posts: 10,313

    saltflats
    Member
    from Missouri

    What are the forging #s
     
  3. Fordors
    Joined: Sep 22, 2016
    Posts: 2,978

    Fordors
    Member

    I think the left crank is 348, but the one on the right is 265-283.
     
    gimpyshotrods likes this.
  4. Marty Strode
    Joined: Apr 28, 2011
    Posts: 5,143

    Marty Strode
    Member

    I read that Reher and Morrison used a 348 crank to de-stroke a big block, for their Pro Stocker.
     
    Junior Stock likes this.

  5. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,360

    56sedandelivery
    ALLIANCE MEMBER

    I wonder if either are W-motor cranks? Reason I say that, is because the old B & M Hydro-Sticks neexded to have the flywheels machined to clear "balance weights", just like 327, 350 cranks have a balance weight (big blocks also). Like another HAMBER said, casting numbers? I am Butch/56sedandelivery.
     
  6. neilswheels
    Joined: Aug 26, 2006
    Posts: 815

    neilswheels
    Member
    from England

    try the 348/409 forum, they'd know
     
  7. 409 has a bell shaped bolt flange while the 348 is round. This may help with ID
    348.jpg
     
    Kan Kustom and Desoto291Hemi like this.
  8. Kan Kustom
    Joined: Jul 20, 2009
    Posts: 2,634

    Kan Kustom
    Member

    Thanks for posting this chart.
     
  9. One may be forged steel and the other cast iron.
     
  10. Fordors
    Joined: Sep 22, 2016
    Posts: 2,978

    Fordors
    Member

    In the 348 era Chevy used forged cranks exclusively, it was later (1963?) when cast cranks started to show up in some 283’s. Also, in the six cylinder engines and even the Chevy II four banger there were cast and some forged cranks.
     
  11. Coreguys
    Joined: Aug 20, 2014
    Posts: 11

    Coreguys
    Member

    Sorry, duh, The one on the left is 3732692, the one on the right is 3824554
     
  12. Coreguys
    Joined: Aug 20, 2014
    Posts: 11

    Coreguys
    Member

    I'll go try that. Thanks. Knew someone would point me in a direction ;)
     
  13. Coreguys
    Joined: Aug 20, 2014
    Posts: 11

    Coreguys
    Member

    Yeah, aside from the flange they are both identical. Just odd that we suddenly noticed the difference in the flanges after all these years.
     

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