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Technical Smith-Jiggers OHV Flathead

Discussion in 'The Hokey Ass Message Board' started by El Caballo, May 29, 2025.

  1. El Caballo
    Joined: Mar 3, 2001
    Posts: 6,332

    El Caballo
    Member
    from Houston TX

    IMG_4005.jpeg
    Most bonkers thing I’ve ever seen on a flathead.
     
    NoSurf, RMcCulley, Sharpone and 7 others like this.
  2. CSPIDY
    Joined: Nov 15, 2020
    Posts: 894

    CSPIDY
    Member

    looks like they converted it into an F head
    and
    What kind of contraption is that distributor?
     
  3. alchemy
    Joined: Sep 27, 2002
    Posts: 22,320

    alchemy
    Member

    Yes, intake uses stock valves but exhaust is now through the head. Magneto on the front is exactly like the one that Ryan had stolen.
     
    seb fontana, SS327, Sharpone and 2 others like this.
  4. winduptoy
    Joined: Feb 19, 2013
    Posts: 3,968

    winduptoy
    ALLIANCE MEMBER

    Yes, it is an F head conversion...way cool if it was in someones car having the snot driven out of it
     
    NoSurf and Sharpone like this.
  5. 302GMC
    Joined: Dec 15, 2005
    Posts: 8,402

    302GMC
    Member
    from Idaho

    Jiggler, not jiggers ....
     
  6. J. A. Miller
    Joined: Dec 30, 2010
    Posts: 2,298

    J. A. Miller
    ALLIANCE MEMBER
    from Central NY

  7. BJR
    Joined: Mar 11, 2005
    Posts: 11,061

    BJR
    Member

    I wonder if anyone knows how much of a HP increase you get with this conversion? Or is it just like putting chrome valve covers on an OHV engine.
     
  8. Sharpone
    Joined: Jul 25, 2022
    Posts: 2,477

    Sharpone
    Member

    Very cool
    Dan
     
  9. Toms Dogs
    Joined: Dec 16, 2005
    Posts: 852

    Toms Dogs
    Member
    from NJ

    Speccie likes this.
  10. s.e.charles
    Joined: Apr 25, 2018
    Posts: 428

    s.e.charles

    so .... were these types of heads ever made for a full size flathead?

    my search gave me 30 hits of "60" reference and most of them only single word references from 20 years ago.

    thanks

    sid
     
    Sharpone likes this.
  11. Ryan
    Joined: Jan 2, 1995
    Posts: 22,539

    Ryan
    ADMINISTRATOR
    Staff Member

    Man… That is a gorgeous motor…
     
    Sharpone likes this.
  12. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,802

    drtrcrV-8
    Member

    A long-gone racer-friend reported that he drove a V8-60 with a set of these, & while they didn't add that much HP, they allowed a lot more RPM.
     
  13. Dave G in Gansevoort
    Joined: Mar 28, 2019
    Posts: 3,488

    Dave G in Gansevoort
    Member
    from Upstate NY

    And cooled better. Got the exhaust out of the block, and if you look closely at the head it doesn’t have any water around the exhaust.
     
  14. s.e.charles
    Joined: Apr 25, 2018
    Posts: 428

    s.e.charles

    c'mon guys. i had the courage to necromance this thread, somebody at least take a guess to make me feel wanted . . . .
     
  15. seb fontana
    Joined: Sep 1, 2005
    Posts: 9,113

    seb fontana
    Member
    from ct

    Not to my knowledge.
     
  16. tubman
    Joined: May 16, 2007
    Posts: 7,959

    tubman
    ALLIANCE MEMBER

    Several vendors made "F" head conversions for full size flatheads (I believe Riley and Tornado were among them,) but they were actually quite different in configuration that these.
     
  17. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,802

    drtrcrV-8
    Member

    A further note : that racer friend said that the screws on the rocker covers had to be safety wired or they would vibrate out due to engine harmonics... This was in the early/mid 1950s
     
  18. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,452

    Ned Ludd
    Member

    EOI engines are unusual. I'm not aware of any which aren't converted side-valve engines. IOE is common enough e.g. the Willys Hurricane etc. The most interesting one is probably Rover's, which featured a angled deck like on a Chevy W-engine.

    The pic doesn't show the spark plug location on that Flathead. Engines like the Rover work well because the intake valve is over the quench area, and the hot exhaust valve is at the bottom of the combustion chamber with the spark plug close to it. Having the exhaust valve over the quench area is less than ideal. The only way to do that would be with a relatively low CR and a longish bathtub-shaped chamber, with the plug on the outboard side of the exhaust valve. That wants forced induction?
     

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