About to buy a 48 Desoto Business Coupe - advice?

[Jacqualine47]

Hi all! I'm new to the forum, new to pre-v8 cars, and new to mopars to boot - so I'm going to be asking quite a few questions.

I'm normally a chevy girl and had actually been working on a camaro project, but I came upon a 48 Desoto Business Coupe that I can get pretty cheap off a friendly old fellow I met recently... and I absolutely fell in love with the car. I've pretty much decided to sell my unfinished camaro project and pick up the Desoto - which the guy tells me I'll be able to drive home! Apparently the story behind the car is that the owner's father was the original owner, and they just kept it up all these years. The motor was rebuilt in the 80s but doesn't have many miles on it, and the transmission was likewise rebuilt. Running gear-wise, he tells me that all it needs is to have the brakes bled, be cranked, and let off the jack-stands - which he'll do when I come over with the money (apparently he also has a brand new 6v battery for it).

I looked over the car pretty well - I found only three spots with rust: two spots about the size of a half-dollar on the interior side of the windshield frame - not rusted through but it looks like a bit more than surface rust, and one spot that is bubbling up a bit on the front of the back driver's side fender. Everything else is solid - just a little surface rust here and there. All of the chrome is pitted unfortunately. The interior is in alright shape - needs some stuff recovered, but all the underpinnings look to be fine (I do some seamstress work and have worked with synthetic leather before, so I actually feel confident about recovering the interior parts myself). All the gauges work and the radio works. The chrome in the middle of the dash is pitted, but not bad looking. The car was on stands, so I didn't get to test the suspension - but I'm told its fine. I'm not sure what the underside looks like, as at the time I wasn't wearing an outfit I was willing to get on the garage floor in - but judging by the rest of the car I seriously doubt that there are any problems with the frame.

So basically, it looks like a drivable car that just needs cosmetic work and some TLC. I do have some questions before I take the plunge and run off to buy it though...

First off, where can one find reproduction parts for these things? Do they exist? I was looking around online and couldn't find a thing... not even new emblems or dash panels

Are there any bolt-on suspension upgrades, or will I be stuck with the stock suspension unless I want to chop up my frame and weld in a camaro or mustang subframe?

Are these cars hard to put a better drivetrain in? I was thinking that I might one day want to replace the flat6 with a v8 with a floor-shift four speed tranny and a stout rear end. I know nothing about flatheads or mopars though, and I despise the idea of cutting up the original steel too much (a hole for a shifter or a bit of massaging the tranny tunnel sure... but I wouldn't want to change the firewall or do anything drastic) Are there any good v8s that use the same motor mount locations and fit without problem? (I know I'd need to make a custom tranny crossmember, but that isn't a big deal). My first inclination was to stuff a 454 and m21 muncie in it since I have some laying around... but I'm leery of putting a chevy drivetrain in a classic mopar (motor mounts would have to be custom, and... well, I've done chevies before)... I've got a good 360 in an old hoopty d150 that could be built... I'd just need to find a nice manual tranny to bolt up to it.

Also, does anyone have a working link to a 12v conversion kit? I searched the forum, but I couldn't find a working link. I can probably do it myself, but a kit would make it a lot easier. Oh, and does anyone have a part number for an alternator that bolts to the original brackets without much problem?

Thanks everyone Once I've got all my research and go bring the car home I'll be sure to post pictures

- Jacqualine

[55 Fargo]

48 Desoto Biz Coupe, Nice Car, fantastic looking grilles on these old Beasts.

Did you check out the floors and rockers, depends on where this car is from, that can bea rust trouble spot, some of these patch panels are available, and to be honest they aren't too difficult to fab, and weld in.

The Pot metal on the trim, is pricey to replate, maybea donor car and/or parts may be in your future, the bumpers can be pricey for re-plate too.

As far as parts source, depends on what parts? Rock Auto and Napa will have wheels cyls, brake kits,carb kits, shocks etc. Rubber parts and weather stripping Steele Rubeer, Roberts, Andy Bernbaum.

Flat Head engines are great power plants, ain't no Hemis, but you can Hot Rod them with shaving the heads, dual carbs, split exhaust/headers, wilder cam, performance heads, electronic ignition.

Interior , well thats your call, local auto upholstery suppliers.

OD Transmissions call George Asche, makes your freeway cruisng a lot more efficient.

Front disc brake kits, see Old Daddy on this forum, he makes the adaptor plates, you buy the rest at local parts store.

So welcome aboard, if you choose to drop ina 360, eat there is some info and experience on thei forum for this too.

12 volt conversion , info is readily available on here too, by uisng a GM single wire alt, and a fabbed bracket, this works well too..............Rock

[55 Fargo]

PS one other thing, can you post a pic of the new Baby, if your able too......

[Don Coatney]

Where are you located? I have a flathead Desoto engine in my Plymouth and I have driven it on several long trips with no issues. No need to plant a shiverlay engine in it. I have also installed a Borg Warner T-5 five speed overdrive transmission, front disc brakes, dual carburetors, dual exhaust, dual point distributor, and a lumpy camshaft.

[Jacqualine47]

Where are you located? I have a flathead Desoto engine in my Plymouth and I have driven it on several long trips with no issues. No need to plant a shiverlay engine in it. I have also installed a Borg Warner T-5 five speed overdrive transmission, front disc brakes, dual carburetors, dual exhaust, dual point distributor, and a lumpy camshaft.

I'm in GA (if you're in GA too, shoot me a PM and I'll be more specific). Those sound like some really nice upgrades. I'm a big fan of the T5 and T56 trannies - though I suspect that the t5 would be more than up to handling the flat6. Is it difficult to get a flywheel/bellhousing/clutch assembly/input shaft to monkey a t5 in there? That sounds like a winning combo if you can get some spunk out of the flat6 - especially with today's gas prices (I believe cars are made to be driven, not to sit on a trailer and put around car shows). I'm very interested in how you did the disk brake conversion as I've never been fond of drum brakes - especially if I'm driving through Atlanta or Columbia.

- Jacqualine

[Jacqualine47]

Did you check out the floors and rockers, depends on where this car is from, that can bea rust trouble spot, some of these patch panels are available, and to be honest they aren't too difficult to fab, and weld in.

Yep, first things I checked... they are solid - which is surprising given the GA humidity.

The Pot metal on the trim, is pricey to replate, maybea donor car and/or parts may be in your future, the bumpers can be pricey for re-plate too.

I'll probably have to start watching the swap meets and ebay - that sucks that there aren't aftermarket repros of this stuff - like the emblems and such. Everything I've ever played with before has had all that stuff easily purchased for pretty reasonable. I guess with these I'm limited to replating the originals or searching the scrapyards huh?

Flat Head engines are great power plants, ain't no Hemis, but you can Hot Rod them with shaving the heads, dual carbs, split exhaust/headers, wilder cam, performance heads, electronic ignition.

With the original tranny, what sort of HP do this things usually put out? I know nothing about flatheads and haven't had opportunity to drive the car yet, but I presume its a bit torquey right at the start and then kinda peters out, right? Depending on how much hopping the flat6 up will cost, I may decide to keep it - certainly would get better mpg than a v8.

Interior , well thats your call, local auto upholstery suppliers.

I've had a lot of luck with Hancock fabrics. I'll probably make a custom two-tone interior for the car since I enjoy that sort of thing. Once I've made my templates for the seat covers and door panels it'll be easy to reproduce as well.

12 volt conversion , info is readily available on here too, by uisng a GM single wire alt, and a fabbed bracket, this works well too..............Rock

I already did a search on the site... I found a few links to kits, but they were all broken - the websites either gone or moved with no forwarding addy. I was wondering if anyone knew where I could get a kit - even just a light bulb and fuse kit would be great. Other than actually mounting the alternator, it seems pretty straightforward - I just have to figure out how to handle the 6v accessories... it seems some people say a voltage reducer on the hot-wire makes it work and others say I need a resistor in the line... so I'm not sure how that works. Electrical systems were never my strong suite unless I have a wiring diagram in front of me LOL.

I'll post pictures as soon as I bring the car home... gotta wait on the guy to come pick up my old camaro project so that I'll have proper space for the Desoto.

- Jacqualine

[greg g]

What fuses??? There is one mounted on the headlamp switch, the other circuits run through 1 30 amp circuit breaker, some might have been updated later, but that was basically it for stock. There may be another one built into a relay under the hood, besides fuses don;t care about voltage, they deal with amps.

Remember you original system is POSITIVE ground. So if you switch there are a couple things that will need attention, the ammeter, and the coil.

If you are switching to a alternator, the simplist way to wire a single wire type is to attach the output wire to the wire attached to the voltage regulator battery post, and abando the others inplace. On the aformention gauge and coil, you need to switch the wires on the terminals.

[55 Fargo]

Hi, these old engines are not known for real neck snappin off the line pick-up, the HP for your Desoto engine would be for a 251 ci, about 116 hp @ 3600 RPM, compression ratio 6.6 to 1, but they are very torquey long stroke engines, bore = 3 7/16, stroke 4 1/2 inches.

These engines get max torque at about 1200 or so RPM, so just off an idle they have there torque punch.

Now with just this stock engine, and usually the Desoto may have come witha 3.73 rear end or a 3.54 read end if it had the 4 spd tip-toe semi-auto trans and fluid drive coupler. It should cruise all day 60 to 65 mph, probably could do 90 mph.

The speed equipment is out there, probably turn this engine into a 150 170 hp engine, but building a 250 to 300 hp engine, ain't gonna happen.

Now what trans do you have in this puppy now, does it have a fluid drive coupler, any idea what diff ratio you have.

These cars with the flat head engine souped up, and a T 5 trans will get you going nicely, the flat head with dual carbs and exhaust sound and run great, fuel economy is not bad too. Some guys in your neighbourhood, Dublin GA, have even installed AC too.

You have 2 great members of this forum right in your own state, try and get to know these fine Gentleman, they are a wealth of knowledge of old Mopars.

Here is a website that sells the disc brake kits, there is install info as well, www.rustyhope.com. Swap mees, forums like this, ebay, will help in your search for trim, there is a 48 Desoto, 3 miles from where I sit, it is in the bush but high up on blocks, near a river delta, but the owner won't sell parts, too bad cuz there are a lot of nice parts on the car, so there will be more all over the USA and in Canada, where I live.

Good luck, keep us posted, this forum, as as well as a few others will bea of trmendous help to you with this car.......

[55 Fargo]

Stock ina 47 Chrsler had a fuse for the radio, and for the heater motor, and maybe the electric wipers, at least mine does now, I also addeda fuse for the lighter and I re-wired as per the 47 Chrysler schematic, which should be very similar to the 47 Desoto.

The positive grnd info Greg is relaying is important, get to knwo your elcetirc system, someone on here can probably post the correct schemetics if you need them....

[JohnS48plm]

You'd have a good chance of finding trim and other parts for the desoto by joining a Desoto club.

Club members usually have parts and give good prices to fellow members. JohnS

[greg g]

And the final warning for the uninnituated. You must have a good parking brake or wheelchocks, as there is no mechanical connection between the engine and the trans, so no PARK and no engine off compression braking. Keep your Desoto home by properly securing it if not parked on a dead level. And alway chock tires when jacking.

[realgonekatt]

Hey jacqualine. You didnt happen to get your desoto From a fellow a little north of cumming ga? I only ask as I saw one up that way recently.

I have installed the rusty hope disc brake kit on my 46 plymouth and I highly reccomend it. (I posted progress pics on this site) Also, the front suspension on these cars is really pretty solid and with a few upgrades (such as shock relocation and chopping a little spring off) they handle fairly well.

I have a few extra parts around the garage so let me know if ya need anything.

I live just outside of roswell ga.

Good luck with your project, much classier than a camero:D

__Bryan

[Jacqualine47]

Thank you all so much for all the great tips! After learning more about it now, I'm definitely going back to pick the car up as soon as the money clears my bank account - it sounds like I'll be able to make a really nice cruiser/driver out of it - which is what I want out of a project since I believe in driving and enjoying the classics

The tranny is the fluiddrive, and I'm getting a spare fluiddrive tranny with the car.

This car is not the one from north of Cumming - I'll post the pictures once its officially mine and I've got it home.

It sounds like there are quite a few people around GA - it'd be fun to invade the Starlight Six Drive-in sometime

- Jacqualine

[greg g]

The transmission is what ever the transmission is, the connection between the engine and the transmission is the fluid drive unit. Chrysler corporation put several different transmissions from three speed standards to a couple different semi automatics called by different names among the chrysler dodge and Desoto lines.

Some good information on ALLPAR search fluid drive and transmissions.

http://www.allpar.com/mopar/m6.html

and the Imperial Club website repair section has a gread section that applies to the Semi autos

Must reading for a future Desoto owner. Good stuff on Desoto land site also.

[realgonekatt]

You had better hurry as the driveinvasion is like next week:eek: I had intended to make it but, as of yet I still lack a gas tank and rear brakes. There's always next year. If you get a chance, check out Hillbillies and hotrods that is coming up in fairmont ga. A little more redneck but a damn good time to be had. And they have an 1/8 mile dirt strip!!

[Jacqualine47]

Thanks for the link! I believe that the tranny is a semi-auto - definitely not the 3spd standard. I'm not sure of the exact model.

- Jacqualine

[Jacqualine47]

You had better hurry as the driveinvasion is like next week:eek: I had intended to make it but, as of yet I still lack a gas tank and rear brakes. There's always next year. If you get a chance, check out Hillbillies and hotrods that is coming up in fairmont ga. A little more redneck but a damn good time to be had. And they have an 1/8 mile dirt strip!!

LOL - I used a poor choice of words - I just meant that it'd be fun at some indeterminate point in the future... totally forgot that they had an event with 'invasion' in the title LOL

- Jacqualine

[PatS....]

Thanks for the link! I believe that the tranny is a semi-auto - definitely not the 3spd standard. I'm not sure of the exact model.

- Jacqualine

1948 would be the M5 semi automatic. The Fluid Drive is the Fluid Coupling that replaces the flywheel.

There is no flywheel on your car, just a unit which resembles a torque converter with a regular clutch bolted to it. It transfers power on a 1 to 1 basis via the fluid and doesn't multiply the torque. The starter ring gear is also part of the Fluid Coupling.

The transmission is a separate unit, in your case an M5, but they also came with Fluid Drive and a regular 3 speed on the tree.

They are surely not speed demons but they are relatively trouble free once you deal with the basics. And they are very unique.

[gnoub1948]

Jacqualine:

I have a '48 De Soto completely disassembled in the garage. Mine is a rust bucket. There's more rust than meets the eye I can tell you. Anyway, I still love him. If you need pictures of things let me know.

I have found a ton of parts on eBay. Lot's of replacement stuff comes up. I've bought NOS fenders and some trim pieces and lot's of dash parts. Being in GA you most likely don't get to the Spring or Fall Carlisle events. I have found lots of things there. Actually, that's where I found the NOS fenders. I imagine Charlotte has lots of stuff too.

I recently had many of the body and suspension parts chemically dipped. What looked like nice pieces came back unusable like the lower control arms. Bu then my car is a South Carolina car that looked like it sat in a swamp for years.

Plymouth Doctors makes lots of replacement parts for the floor and some body panels.

I have learned the hard way that I should have bought a parts car right away. You can find cheap ones and it's well worth the expense regardless of the condition of your car. Recently I bought a very nice set of door hinges since mine were shot. But the cost was $300. You can buy a whole car for $1,000 or less.

Gary