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Technical Flathead ID Confirmation Help

Discussion in 'Traditional Hot Rods' started by dcadwell, Apr 8, 2014.

  1. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    I picked up a complete engine and had some difficulty IDing. There are no date codes stamped in the usual place. There are no raised letters on the bell housing, just a lot code.

    The one thing the block does have is a raised intake surface (see photo). The heads have a lone A cast into them, and 81A stamped (1938-1941?). All the cylinders are sleeved and are at 3 1/16. The stroke is 3 3/4.

    Given all this, I'm guessing it is a 1941 WWII military engine. Am I close?
     

    Attached Files:

  2. jetmek
    Joined: Jan 12, 2006
    Posts: 1,847

    jetmek
    Member

    39-40 could be merc or truck tincan sleeves and steel pistons if the sleeves are worn you mite get away with pulling them and boring to 3 3/16 but beware of rust thru at bottom of cyl walls
     
  3. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 694

    ronnieroadster
    Member

    The block is 1940 usually found in Mercury's. Get the sleeves removed and then have the block bored to the standard bore for the 100 horse flathead which is 3- 3/16 that's what I always do with those factory sleeved blocks.
     
  4. Fortyfordguy
    Joined: Sep 16, 2002
    Posts: 644

    Fortyfordguy
    Member

    The "raised" intake surface did not show up til 1941 models and was discontinued very early in 1942 production.
     
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  5. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    Thanks very much! I was wrong in thinking that the only blocks with factory sleeves were military. The pistons are aluminum. I assume if it was a Mercury it would have the 3 3/16 bore, but it doesn't (yet). So far it looks buildable. Another project on the list.
     
  6. This came up in another thread last week, and we id'd it as a '41 or '42 from memory because of the raised intake deck. Van Pelts has a good table of identifying notes.

    As a side note, i have a '37 21 stud with a raised intake deck.. so it was introduced earlier than '41, but again not in the 24 studs until '41. Do not know the reasoning for the couple of year gap of a flat deck.
     
  7. alchemy
    Joined: Sep 27, 2002
    Posts: 13,701

    alchemy
    Member

    Are there freeze plugs in the pan rails?
     
  8. 38 coupe
    Joined: May 11, 2008
    Posts: 155

    38 coupe
    Member
    from Texas

  9. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,613

    Bruce Lancaster
    ALLIANCE MEMBER

    Or wartime. Same Ford an Merc blocks used through WWII. Sometime during war a circular boss (kept on postwar engines) was added near the 2 oil ports at back to create drilling location for third port used n carriers with cooler and heavy trucks with full flow filter. This seems to have been done to make Ford USA engines fully adaptable to Canadian and British uses, which were supplemented with US engines and parts.
    " no date codes stamped in the usual place..." Huh?? Date codes?
     
  10. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    Thanks for the help, and for the link - that thread didn't come up in the search I did.

    The block does not have the freeze plugs and does have the curved surface between the exhaust ports. Everything is consistent with being a 41/42.

    The date codes I was referring to come from my experience with an 8BA that has the letter/number/letter stamp giving the month/day/year. I don't know when this was started.

    With all this new information, I have another block that I thought I knew since it came from a 41 truck. A weak link though since 70+ years have gone by. 24 stud, passes the pencil test and has trapezoidal center cooling holes, .030 over 3 1/16. It does not have freeze plugs, (41/42), but it does not have the raised intake and the block is flat between the exhaust ports (39/40). It seems to fall in between. Oh well - knowing it is somewhere in that range is good enough for me.

    Thanks,

    Don
     
  11. 38 coupe
    Joined: May 11, 2008
    Posts: 155

    38 coupe
    Member
    from Texas

    dcadwell, can you post pictures of the last block you described? I am still collecting pictures and gathering data.

    Thanks.
     
  12. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,613

    Bruce Lancaster
    ALLIANCE MEMBER

    Exceptions and anomalies continue to accumulate!
     
  13. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    Here are some pictures. I'm interested to hear what you think.

    Thanks!
     

    Attached Files:

  14. That has plugs in the oil pan rail......'41... Is my guess.....
     
  15. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    Irish Mike - you are right, it does have the plugs. It was caked with so much crap when I initially looked at it I missed it. I scraped it off for the photo and didn't take a fresh look. Pretty stupid on my part.

    So, if it has the freeze plugs, flat sides and non-raised intake, wouldn't it be consistent with being a 38/39 rather than a 40/41?

    Thanks!
     
  16. 38 coupe
    Joined: May 11, 2008
    Posts: 155

    38 coupe
    Member
    from Texas

    It looks like a 39-40 Ford 221 block to me. The 1938 24 stud blocks look the same on the outside but won't take the longer crankshaft without a ton of work to the crank.

    Thanks for posting the pictures.
     
  17. dcadwell
    Joined: Mar 13, 2014
    Posts: 21

    dcadwell
    Member

    Thanks 38 Coupe - I appreciate your willingness to share your expertise.
     

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