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Mopar flathead 6 motors- whats to be expected

Discussion in 'The Hokey Ass Message Board' started by Modeljunkie, Dec 8, 2011.

  1. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    It would actually be cheaper and easier to sell the DeSoto and buy a later model car with V8 and automatic if that is what you want.
     
  2. 64 DODGE 440
    Joined: Sep 2, 2006
    Posts: 4,009

    64 DODGE 440
    ALLIANCE MEMBER
    from so cal

    Where is the fun in that? o_O
     
  3. 73RR
    Joined: Jan 29, 2007
    Posts: 6,230

    73RR
    Member

    Note to Nix50, don't let Rusty get to you....he is not much on making mods to the old Mopes, especially the funky transmissions. He clearly loves those things...the rest of us, not-so-much.

    If you can find a late 50's 'something' in your old bone yard with a 23" or 25" engine and TorqueFlite (even a PowerFlite) then that is a good direction to go. Trans rebuild parts are available and you will be using 100% oem stuff and will only have minor changes along the way.
    If you swap to a late TF then you will have a fairly major project on your hands. I don't recommend the swap to the novice or those on a budget.
    If you want pics of the TF adapter troll through my web site.

    .
     
    Flat Six Fix likes this.
  4. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    73RR what would you charge a customer to find a 57 - 59 Mopar flathead six Torqueflite and install it in a 49 DeSoto? What would you estimate the parts and labor to be? And would it be better to use the pushbuttons or change to a gearshift lever?

    I ask purely for information. The OP stated that he is on a budget and I am sure he would appreciate knowing what he is letting himself in for before he tears his (running) car apart.
     
  5. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    I don't love the Fluid Drive or the transmissions that go with them. If I had the choice I would take almost anything instead.

    Unfortunately if you like Dodges, DeSotos and Chryslers from the 1940 - 1954 period you don't get much choice.

    The easiest swap would be a 3 speed manual from the same period. If you had a Plymouth or low line Dodge to cabbage the parts off of, you could do the swap in a couple of days using ordinary hand tools.

    They really aren't that much different from a regular automatic and in some ways, they are better.

    For example if I were transported back to the early fifties and I was looking for a car to tow a large travel trailer my first choice would be a 1951 to 53 Chrysler Saratoga, New Yorker or Imperial with hemi head V8 and Fluid Torque Drive.

    In this type of service the 4 speed trans + torque converter would be far superior to any manual trans, 2 speed torque converter trans, or Hydramatic 4 speed + fluid coupling.

    Not to mention the unbeatable Hemi V8.

    We get guys asking about changing from a Fluid Drive to some other transmission every week or 2 and we always give the same answers.

    But for some strange reason, not one person reports back with a successful conversion.

    I stand by my opinion that the Fluid Drive and semi auto trans is not as good as a modern automatic but, the difference is not worth the bother of changing.
     
  6. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 921

    Flat Six Fix
    Member

    Well the Fluid Drive and L head 6, will never be neck snapping that's for sure.
    I have driven a few of these, 48 Chrysler and M5 trans FD semi-auto, very neat trans but so so slow off the line in high range, a real dog in that combination.
    Have also driven a few Dodges with FD and 3 spd, not so bad, can also be driven as a manual or stay in 2nd gear around town, kind reminds me of an ATV type driveline.
    I also had a 47 Chrysler with an engine from a 1951 Canadian Dodge, 25 inch 218, dry clutch, 3spd trans, and 3.73 diff. This was a very easy conversion, not a bad drive either, b ut not neck snapping, not too many flathead 6s are.
    My current "jalopy" 55 Fargo truck, with a 25 inch flattie, not sure if its a 228 or 251, never popped open the plug on the head to find out.
    This engine has good oil pressure starts easy, is 12 volts, but with a Acme T98 4 spd trans, and 1980s Mopar 8 1/4 diff 3.23 gears, she is a bit doggy, and seems to be out it's power band at times with this combo, but she is okay.
    I have never driven or had the pleasure of seeing or driving a souped up flattie, with either dual or tri carbs, split exhaust, hot cam shaved head etc.
    I sure wish I had the opportunity to experience and engine and driveline like this, before I decide to create one.
    So if any of you can enlighten me on say a 251 or a 265 or even a 230 souped up, and what I can expect to see that would be nice.
    I have watched videos, and read some comments, but have never had the pleasure firsthand on one of these beasts.
    having said all this, I know it may be cheaper to drop a 318/360 or even a SBC into my truck, but I do like the flattie engines....
     
    Last edited: Sep 9, 2015
  7. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    How is your compression? How many miles since it was rebuilt? Unless the engine is in top shape better not modify it, you will shorten its life considerably.

    If bearings, valves, rings etc are good then go ahead.

    They respond to the same hop up measures as any other engine. More carbs, dual exhaust or header, cam, high compression. The problem is not too much speed equipment is available and it is expensive. So you have to make your own to a certain extent.

    I like the idea of a centrifugal supercharger. For certain technical reasons flatheads respond well to supercharging.

    Watch your Craigslist and Kijiji ads, McCulloch SN60 superchargers off Mustangs come up for sale regularly, for a few hundred bucks. If you adapt one onto your stock motor you can get 30% to 40% more rear wheel horsepower with no other mods and no reduction in drivability low speed power or smoothness.

    O ya, another forgotten trick that was popular in the early hot rod days was lightening the flywheel. A machine shop can cut off 10 pounds of iron off most flywheels for whippier acceleration.
     
    Flat Six Fix likes this.
  8. 73RR
    Joined: Jan 29, 2007
    Posts: 6,230

    73RR
    Member

    Good points Rusty, and I also would really like to hear of a completed project swap to see how that particular individual approached and managed the work. I have never suggested that it would be easy and I certainly would never suggest doing the work in the driveway! Just swapping one pile of oem parts for another pile of oem parts can be problematic enough without adding in for different years/makes/models.
    The value of changing, the 'bother' part, is the hot-rodding part and it is just done...well, because....
    Nix50 says that he has a old yard nearby so if he finds a L6/PF or L6/TF intact then whatever shift arrangement is attached should be used. Nothing wrong, IMHO, to mounting the PB assembly in a new location in the subject vehicle. Maybe not today, but in years past there were plenty of 'button drives' grafted into a new dash or mounted in a floor tower. This is the hot-rodding portion of the build.

    Cost? You can't put a price on 'love'....but you can charge by the hour.
    It would be prudent for anyone asking similar questions, in this thread or any of the many similar threads, to first decide if he has the ability to do the work. Then, if the words "on a budget" are invoked any outside help will remain outside and the project goes nowhere.
    There are multitudes of talented single-car-garage guys who could do this swap in short order; we just don't know who they are.

    .
     
  9. Nix50
    Joined: Sep 4, 2015
    Posts: 8

    Nix50

    73RR and Rusty,
    Man, I came to the right place for advice. Your debate in the last few entries has been very informative and enlightening. The reality is, the DeSoto transmission seems to do most of what it is supposed to do except that it leaks at nearly every seal, doesn't down shift and the clutch is slipping. To fix the leaks and the clutch, I would need to pull the tranny anyway. The down shift may be something deeper but seems to work better when the tranny's full of oil, however, it just doesn't stay in there long.
    Originally I was looking for a "simple" bolt in full auto replacement since I was gonna have the tranny out anyway. But now I am looking at 6 of one and a half dozen of the other. I have a good service manual and will study on the transmission a bit more, might just fix the original one. I'm not trying to increase performance really, was just interested in making it more driver friendly. No intention of hopping up the flattie, maybe some dress up if I can find the right stuff, but that's about it.
    I'm no stranger to mechanic work, but you both make a good point about the budget and working in the garage. It is fairly tight quarters and may not be suitable for a conversion project. I will be going out to the salvage yard again soon to see what he's got. However, If he's got a good PF or TF behind flathead six, I might give it a whirl.
    I want to thank you both for your help, it's all good advice.
     
  10. Nix50
    Joined: Sep 4, 2015
    Posts: 8

    Nix50

    And Rusty, I don't want to get rid of the DeSoto. Don't know if I will learn to love the Fluid Drive, but I could easily learn to tolerate it. Look at the big 'ol grin on the front of that car, how could I not love it?
     
    73RR and Flat Six Fix like this.
  11. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    How many miles on the car? If the engine is as tired as the transmission you might consider changing the whole power train. It wouldn't be much more work or expense to swap in a V8 engine and automatic, than to change the trans. But if you do this you need to install a different rear axle. Because of the hand brake, and to get a better gear ratio.
     
  12. Nix50
    Joined: Sep 4, 2015
    Posts: 8

    Nix50

    Hi Rusty,
    The guy I got the car from had the engine rebuilt about 2 years ago, it's quite fresh and runs strong. Unfortunately he did nothing with the transmission. I have considered the V8 swap, but I think that takes away a lot of the character. Although, I won't completely rule it out. I like the sound of the flathead and a well dressed one stands out at the local hood raisers. If the best way to keep the flathead is to keep the Fluid Drive, then the Fluid Drive it might be. If it was working proper I might be more of a fan, time will tell. Thanks for your feedback.
     
  13. LongLiveFlathead6
    Joined: Feb 20, 2015
    Posts: 49

    LongLiveFlathead6
    Member

    Nix...

    I totally respect your decision to keep the flat 6... With so many V8 swaps out there, no wonder why they spend alot of time under the flatty hoods at events. I understand you loose the performance and the thrill of speed, but how many guys do you know that take there V8 cars to these events and drive them that hard. Some do, most don't...

    I'v seen and heard alot of guys that spend alot of money on V8 motors and plenty of performance parts, and then they paint them, chrome them, make them look like it was on a TV reality show and then never take there high valued rod over 65 mph. Atleast with a flathead 6 and a 3-speed you have an excuse to go the speed limit...

    Regardless, it was rebuilt 2 years ago and it would be a shame to have it removed... I say keep it, and I really hope you do...

    Good Luck!
     
    Nix50 likes this.
  14. dumprat
    Joined: Dec 27, 2006
    Posts: 2,303

    dumprat
    Member
    from b.c.

    No if somebody would post up some good flowing and good sounding exhaust systems that would be great. None of this weld on an extra outlet on the sock crap either. This it a hot rod site after all.......
     
  15. 73RR
    Joined: Jan 29, 2007
    Posts: 6,230

    73RR
    Member

    Remember that the iron exhaust manifold connects to the intake under the carb so you have some pre-heat.
    It could be incorporated into a tube exhaust but most folks ignore it...that's ok if you only drive when the air temp is above 60° but an iced up carb is no fun.
    ...and split manifolds came decades before tubular exhaust so it is the original hot-rod part.....

    And to Nix50, one of the biggest headache with installing any 'new' or 'different' trans is that you lose the rear engine mounts that are on the stock bellhousing. Even a similar, but later, L6 package may not be a direct bolt-in so out comes the blue tip wrench....same process if you install a 'normal' TF, there will be some fabrication work to install new rear mounts. Consider also that the later transmissions also require part-throttle kick-down linkage attachment to the carb. Yes, very doable, but the complete lack of actual demand has kept everyone from marketing such a 'kit' so you get the pleasure of doing the work. Fun? Sure.....well for some of us maybe......

    Keep us posted as you go. As a group, there is something like 10,000 years of varied experience/exposure to draw from.

    .
     
    Last edited: Sep 10, 2015
    Nix50 likes this.
  16. dumprat
    Joined: Dec 27, 2006
    Posts: 2,303

    dumprat
    Member
    from b.c.

    No that would make it an original street car part. More along the lines of an early custom.
     
  17. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    If you can handle shifting a 3 speed the easiest conversion would be to a Plymouth or Dodge stock manual trans. I happen to have a 55 Dodge 6 cyl 3 speed sitting in the driveway but you are probably too far away.
     
  18. Truckedup
    Joined: Jul 25, 2006
    Posts: 3,846

    Truckedup
    Member

    I haven't read every post here.......I kinda remember reading how a fluid drive hi low four speed was changed into a regular clutch manual shift 4 speed... Is this possible ???
     
  19. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,994

    Rusty O'Toole
    Member

    It might be possible with a lot of work but it would be pointless with all the 4 speeds and 5 speeds available today.
     
  20. Nix50
    Joined: Sep 4, 2015
    Posts: 8

    Nix50

    Rusty,
    Although Canada is not far from me, Ontario is on the other end. I'm in North Idaho, about 90 miles from the border. I am not too interested in the manual though, there is a couple of cruise/parade events every year in our area. Tried a manual in one of those a couple years ago, all the starting and stopping really aggravated an old knee injury. But, the rest of the family had a great time. I would like to be able to give em that and still be able to walk the next day. The Fluid Drive will fit the bill for parades. I'm going to look into fixing the F D before I make any conversion plans.
     
  21. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 921

    Flat Six Fix
    Member

    Try this outfit for M5/6 and Fluid Drive prts and service, reputed to be 1 of the best in the country. http://nwtparts.com/
     
  22. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 921

    Flat Six Fix
    Member

    Here try these on for size....


     
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  23. dumprat
    Joined: Dec 27, 2006
    Posts: 2,303

    dumprat
    Member
    from b.c.

    The second one is Moose's and the third is Dynaflash6's I like the sound of Dynaflash's.

    Small diameter tubes I think. Looks about 2". Should work.
     
  24. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 921

    Flat Six Fix
    Member

    Here is another of Tims flatties.
    Its a 265 high perf with tri-carbs, split exhaust, lots of torque with this baby.
     
    unclescooby and DOCWHIT like this.
  25. wizard0ne0
    Joined: Sep 9, 2015
    Posts: 11

    wizard0ne0
    Member
    from Denver

    I am continually amazed at these motors. They seem to always start first crank, regardless of conditions. Honestly my 50 dodge starts easier than my 02 ranger does on cold days.
     
  26. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 921

    Flat Six Fix
    Member

    Yup they sure do, my 251 flattie, starts super easy, with points igntion, even after sitting for a while. Just need to get a little more power out of her though.
     
  27. bomcadillac
    Joined: Jul 14, 2013
    Posts: 27

    bomcadillac
    Member
    from Las Vegas

    My original engine sheared a camshaft lobe. I have a newer engine out of an airplane tug! In pretty sure it's larger displacement and it will mate to a 727 trans! I'm swapping to a V8 if anyone wants the flathead
     
  28. How much for the flathead
     
  29. oldwood
    Joined: Mar 13, 2010
    Posts: 898

    oldwood
    Member
    from arkansas

    I didn't know much about these Flathead mopar motors. I've had a few /6 motors but I just bought a '59 Dodge with a 230 and 3 onda tree. I'm working on get it running. I pulled the plugs out to soak down the cyl's and found this freeze plug issue.
     

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  30. oldwood
    Joined: Mar 13, 2010
    Posts: 898

    oldwood
    Member
    from arkansas

    I know there isn't a BIG following for these types of cars on this site but I wanted to give you an update It was last tagged in 1986. After soaking cyl's and replacing freeze plug and fuel pump I hooked up aux gas tank and started cranking and it fired off. There was so much smoke the neighbors thought something's on fire. I shut it off and rebuilt the carb and brakes knowing that this car was going back on the road. Here are the latest pics!!! Who needs a windshield when its 85 degrees and sunny.
     

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