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53 plymouth engines? Help!

Discussion in 'The Hokey Ass Message Board' started by Zombisleeve, Sep 9, 2011.

  1. Zombisleeve
    Joined: Jun 21, 2011
    Posts: 29


    Hello, I'm currently rebuilding a 53 plymouth cranbrook and have been tossing around some ideas for the engine, I would like to keep it mopar and would also love to keep it a flathead (my 218 is in pretty rough shape) but I've been told they are pretty gutless. what would you all suggest for an engine. as a general idea I'm not looking for a tire burner just something that's reliable and I can cruise at a good highway pace with.

    Also with changing the engine what transmissions would either bolt up or work with minor mods? I'd like to keep it a manual. I'm also curious on space, the 218 sits pretty close to the firewall as it is, would a small block fit just as snug or would I need to reform the firewall?? any suggestions are greatly appreciated!!!

    thanks everyone,

  2. moparmonkey
    Joined: Aug 14, 2009
    Posts: 565

    from NorCal

    The old mopar flathead 6's are not power monsters, but there are a few things that can be done to them to pick things up a bit. If you can find a 230 crank, for example, you can add a few quick cubes. Vintage Power Wagon sells them on the web. The next big item is compression, stock the 218's were around 7:1. Depending on your head, you can shave quite a bit off of them, .050" isn't a big deal, and I've heard of as much as .080 or .090, but you can run into valve clearance problems there. That will add some compression and increase the horsepower. Cams are out there too, although you want to be careful because you're tuning more for torque than horsepower, with the long stroke you're not going to get a ton of RPM's. Edgy makes cams (and aluminum heads and other goodies) for the mopar flatheads. Intake manifolds manifolds with 2-3 carbs are also out there, same as exhaust manifolds and headers set up for a true dual exhaust.

    Add all of those things and you'll have a strong running flathead. It still won't leave to many folks in the dust, but you shouldn't have any problems driving on the freeway either if you gear it right.

    Engine swaps to small block mopars have been done, there are several threads running on here, a search should find them.

    Here's some links for the flatty...


    Vintage Power Wagons (lots of 218/230 parts once you get past the truck stuff)

    Stovebolt (mostly GM flathead stuff, some mopar pieces too though)

    Quality Engineered Components (73RR on here, mostly hemi stuff but also sells transmission adaptors for the 218/230 engine to more modern transmissions, OD, etc)
    Last edited: Sep 9, 2011
  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,967

    from Quincy, IL

    An acceptable level of performance (power) is a highly personal preference. I tend to 'grade on the curve'. In other words, if running a flathead six (and I do), I simply don't expect V8 acceleration and try to enjoy the kind of car I'm driving.

    To wit, I have a '49 Plymouth Club Coupe that I've owned since 1995. The original 218 was sickly when I bought it but I had a '51 Dodge 230 laying around from another project. I rebuilt the 230, installed it the '49, along with a '55 overdrive trans and it has been a very pleasurable driver for several years. If I were doing that project today, I'd likely use a BW T-5 tranny, mostly because the original Mopar OD are getting scarce and pricey.

  4. Davyj
    Joined: Jul 11, 2011
    Posts: 442


    Those flathead 6 engines are still plentiful, we have one in a tow motor in our shop. I know they also were used in sidewalk snow plows up here until just a few years ago. So parts are readily available. I would look into upgrading to a overdrive tranny, and keep it simple......................more fun, with more money left in your pocket.

  5. dougrite67
    Joined: Feb 10, 2012
    Posts: 2


    1 have 1953 dodge mayfair (canada) same as cranbrook came stock with 251ci flathead six. chrysler also had 265 six all 25inch heads yours is 23inch more cubes is always better
  6. I agree with the above..."acceptable" power level is relative.

    my 230 flattie six made 172 on the dyno. by comparison my '93 Grand Marquis 4.6L is rated at 190 h.p.

    the stock 230 in my '50 Wayfarer was perfectly driveable (to me) with only the addition of dual carbs and dual exhaust (NOT the 172 build mentioned above)
  7. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    from Texas

    The Plymouth 218 and Dodge 230 are the same but for the crankshaft.
    The DeSoto and Chrysler sixes are longer in length but stronger overall.
  8. George
    Joined: Jan 1, 2005
    Posts: 7,405


    If you want info on a 318 install use search, truck load of Threads on doing that.
  9. I agree 100%. No need to do a V8 swap. The 230 in my '48 Plymouth has an EDGY head and cam, Offy two carb intake, split exhaust, lightened flywheel and an overdrive. It will run down the highway at 70 mph all day long with no issues and return respectable mileage in the 18+ MPG range.

    Attached Files:

  10. PS~ If you want to get really trick, have Earl (EDGY) cast up another one of his F heads. We have one in our '35 Dodge Bonneville push truck and it's one hell of a motor!

    Attached Files:

  11. hillbilly4008
    Joined: Feb 13, 2009
    Posts: 2,917

    from Rome NY

    Ive got a '53 Desoto with the Canadien version of the 251. So far i've shaved the head .050, and split the stock exhaust manifold. That really woke it up. I also have the M6 tranny behind it, that really sucks for todays style of driving. Its terrible in stop and go traffic, and you'll never win at the drags.
  12. Well i had a 53 cranbrook that was stock, outside of a rebuilt flat six. I thought she had adequate power for around town and with the overdrive tranny, pretty nice on the freeway. You could always find a later 230ci flat six if you want more power, or rebuild and hot rod the one youve got.

    Though i did have a friend with a '54 savoy and he said it was an easy swap to put a 318 into it, it just had to be set a tad forward due to the steering gears position.
  13. George
    Joined: Jan 1, 2005
    Posts: 7,405


    Actually about 1 1/2" to the pass side...
  14. How about a 225 Slant Six? They're economical, dependable horsepower and you can "bomb" the hell out of them. Just a thought.
  15. 73RR
    Joined: Jan 29, 2007
    Posts: 6,552


    The 'leaning-tower-of-power' consumes alot of a 40's or 50's Mopar I think an A-LA is easier.

  16. Country Gent
    Joined: Feb 22, 2010
    Posts: 562

    Country Gent

    If you like the idea of inline 6, give the 225 Slant Six some thought. You can really pump them up and your starting with more modern parts. if it's V8 your lokking for 318s and 360s with a 727 tourqeflite.
  17. Skeezix
    Joined: Jan 10, 2007
    Posts: 845

    from SoCal

    My brother did (had done) 49 Dodge four door with a Jasper 360, Richmond 5 sp with a Dana 60 rear.
    It was scary and the guy that bought it was last seen smiling BIG.
    Was also necessary move over to pass side to clear steering a lot of work but was like driving a Cup car
  18. hkestes
    Joined: May 19, 2007
    Posts: 565

    from Plano, TX

    I agree with Pete. I am running almost the same setup in my 48 Plymouth coupe with the exception that I am still running a stock cam. Not a drag racer by any stretch but a great cruiser without a doubt. On my round trip to the HAMB Drags from Dallas I got 19.98 mpg.
  19. George
    Joined: Jan 1, 2005
    Posts: 7,405


    As Gary said...the /6 needs a wide engine bay for best results.
  20. hkestes
    Joined: May 19, 2007
    Posts: 565

    from Plano, TX

    And is about 7 inches longer than the flathead.
  21. yetiskustoms
    Joined: May 22, 2009
    Posts: 1,930


    im didtching the 6 in my 54 savoy if it will ever die. just keeps going! will do the 318 transplant when the time comes!

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