I have not been able to locate any answers elsewhere on the web.....maybe somebody here may be able to help. I have a 1948 Desoto that has a 237ci flathead. I am interested in obtaining an transmission adapter so I may be able to use a 904/909 auto transmission. When I first bought this car I was intending on using the slant 6 engine in it, but the engine is in remarkable good condition, I hate to remove it. The fluid drive trans that is in it leaves little to be desired when it comes to speed. I have not located an adapter as of yet, but is it possible to create one?..... I have some machining experience, just don't have the engine and trans in front of me to see if it is possible. to make.

Anybody in here who has messed with these engines and willing to give some performance tips? Vintage Power Wagons has a performance cam available for this engine, as for other performance parts....I am at a loss. I plan on modifying the intake to adapt the carburetor off of an old slant 6 that I have laying around. Not planning on a speed demon, just something different and unique.

Thanks
Kenny

As far as I know, nobody ever had a flat 6/904 adapter plate in production. It is apparently possible to convert your trans to a 3-speed manual. The folks at this site could probably give you specific advice about that:


http://www.merc583.addr.com/mopar/frame ... meset.html


Here's a quote from that site r.e. fluid-drive:

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"The biggest repair problem with Fluid Drive is seal leakage where the transmission input shaft mates into the housing. Any leakage will quickly ruin the clutch disk. Repair kits are available but difficult to find. So are experienced repair personnel. Using the correct replacement fluid can go a long way in extending the service life of your unit. Otherwise the units are factory sealed. Carburetors used on Fluid Drive cars are different than the non Fluid Drive models. The Fluid Drive adds some drag on the engine and a dashpot is used to slow throttle closing, thus preventing engine stalling. The adjustment of the dashpot and replacement of Fluid Drive seals are addressed in detail in the factory service manual. Lastly the same manual 3 speed transmission (Type C) is used on both Fluid and non Fluid Drive applications with one part change. The Fluid Drive transmission has a slightly longer input shaft to accommodate the greater depth of the coupling. The shafts can easily be replaced making a standard 3 speed into a fluid drive version and vice versa".

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Offenhauser still makes a sharp-looking, finned aluminum 2 X 1bbl. intake for these engines (#2691) if that method of enhancing induction interests you. Until a couple years ago, there was an outfit called Phillips Performance in the northwest that made repop Fenton cast iron split exhaust manifolds and finned aluminum side covers for the Mopar flat 6. Unfortunately, they appear to have gone out of business. Fenton made a finned-aluminum, high-compression head for them years ago, but those are pretty rare these day as they are long out of production. Phillips had plans to repop them, but don't seem to have gotten to it before they went belly up.

If you'll PM me an e-mail address, I'll send you photocopies of an oldtimer's performance build tips for this engine. They were strong racers in their day.

Good luck.


---Red

The things to look at on your flathead is where the starter is located and how large the current ring gear / flywheel is.
The SL6 starter mounting is up pretty high, my guess is that you may be better-off using a V-8 904, (or 500 OD unit) just because the starter may be in a better position.

As for making the plates, I have done this using bellhousings as templates. Transfer the lay-out onto thin plywood or thick "chipboard" (cardboard) to get everything "engineered" before starting-in on metal cutting. I made a centering "pilot" and used a dial indicator to keep the two bolt patterns on center. A drill press and a metal cutting band saw are two good tools to have access to.
DD

There is a bunch of flatheaders on http://www.inliners.org . They may be able to help. Also do a google search on "PLYDO". These guys sell a lot of parts for the flatheads.

There were some modern automatics used with the industrial flathead applications. I believe the old iron Torqueflite came with some flatheads in the '50s. Someone on Inliners.org found an adapter plate for a A727 out of an airport tugger. I think this is 23-inch 230, but I believe the bell housing bolt pattern is the same as the 25-inch long 237.

Search for this "Mopar" thread "1969 flathead 230...........yes, 69!"

http://www.inliners.org

Thanks for the advice and insight. After looking at the 904 more closely, it appears that it will be too tight of a fit. It may work with a different style starter. I have a 727 trans that was attached to a 318 that was in an Aspen. It looks like that may be the best choice. I have located a company 45 minutes just up the road from me that makes the split headers. I also found the dual carb intake and an aluminum head.


http://www.inliners.org/Advertisers/kkk_ad2.html

budbandy, I also have a '47 DeSoto Custom Club Coupe with the original motor and the 'Tip Toe' semi-automatic transmission. Good luck with the car.

Here is a link to a pic of mine:
http://www.desoto.org/members/page8.htm

I have owned it for about 6 years now and slowly have been piecing it together. Once I complete the parts collection, I will have it all re-chromed, reupholster the interior, and have the car repainted. It is one of those projects that keep steam rolling into something bigger. The satisfaction from driving it and the smiles that I get seem to make all of the effort worthwhile.

I bought two Dodge Aspens just so I could decide on what engine combination to use. Since the flathead is repairable, I have no use for them at the moment. I had intended on using the torsion front suspension from the Aspen/Volare., but that is a big job to undertake. Who knows when I will install it. Once the engine is out and the front suspension is exposed, maybe then.

The front suspension on the DeSoto isn't too bad. I believe it has some bump steer, but that's also problem with an Aspen suspension. PlyDo and I believe Fat Man Fabrication have inexpensive kits to add disk brakes and update the shocks on the stock front end. It's a very cheap mod because some late model parts almost seem to be made for these Mopars, the kit is just some brackets, you get the rest of the parts at an auto parts store. I wouldn't change out the suspension considering how easy it is to upgrade. I've heard that the modern shocks really help the handling. There is a book, I believe by Tex Smith which details this upgrade - very low cost, and worth the effort more than swapping out the entire suspension.

I've wondered whether it might be practical to convert the Fluid Drive to a modern torque convertor. The transmission is a four speed sliding gear, which effectively has a high and low range. The F/D only has 2 units, whereas a T/C has a stator, which creates torque multiplication. I think it might be possible to swap in a T/C, but its probably too expensive(unless you have a helpful machinist friend). I believe a T/C would greatly boost the performance of these cars.