Are the Desoto flatheads the same monster as Plymouth/Dodge

[54Illinois]

I have a ton of 54 Plymouth 230/218 engine parts.  My father is eyeballing a 51 Desoto.  Besides pistons, rods, valves will most parts interchange?  My motors book describes all the Dodge, Desoto, Plymouth flatheads to reference the Chrysler section.

 

Thanks

[martybose]

I thought that Desotos always had the 25 inch motor, not the 22 inch motor that are in our Plymouths.

 

Marty

[desoto1939]

As marty stated the engine block is bigger, 25 inch block.  The baisics of the engine and how it works will be the same but the internals will be differnet because of the size.  The water distribution tube is the longer one, etc same for the head.  ALso the suspension parts will be different. What I have found with my 39 Desoto is the the 39 Ply/Dodge long wheel base models some of the suspension parts will interchange but the regular 39 Ply/Dodge will not fit.

 

So the best thing is to get a 51 desoto parts book and then also the 54 pLy parts book and compare the numbers to see if anything matches, but Iwould think most will not.

 

Rich HArtung

Desoto1939@aol.com

[greg g]

The Desoto block is the same as the Chrysler block, as stated it is longer and the length presents some challenges in trying to install it in a Plymouth. I believe that is why Plymouth almost always rode on s shorter wheelbase than its corporate cousins. That 2 inches need to be accommodated forward of the bell housing cross member.

[Don Coatney]

A 25 inch Desoto engine will fit in a Plymouth but not exactly a bolt in. Most external bolt on parts are the same such as water pump, fuel pump, starter, generator, etc.

 

 

 

[De Soto Frank]

Fundamentally, they are similar in design and construction, but aside from "accessories" like Carburetor, Fuel Pump, and Generator,  they generally do not share parts.

 

As the previous posters have stated, Chrysler & De Soto blocks are 25 inches long, while the Dodge and Plymouth blocks are 23 inches long.

 

Also, most 1939-'54 Chrysler and De Soto sixes are going to be equipped with Fluid Drive Fluid Coupling, which means a different bell-housing, clutch, and transmission.

 

 

Don Coatney has successfully re-worked and installed a De Soto Six  into his P-15.

[GlennCraven]

Don, how big was the shoehorn you used to get that engine in your car?

[RobertKB]

That's the nice thing about Canadian cars. Every Plymouth, Dodge, Desoto, and Chrysler built in Canada from 1938 onward had the long block engine. Makes finding an engine a whole lot simpler. My '48 Dodge D25 and my '53 Plymouth both have the long block engine. My current project, a 1951 Dodge business coupe has the same long block engine. Canadian Dodges are basically Plymouths with Dodge trim. A while back there was a comparison of the front of the frames between a US Plymouth and the Canadian equivalent and they are slightly different so the Canadian cars can take the longer engine. The radiator support is also different so the radiator sits 2" further forward. It was just a matter of economics why we only had the one engine length. Canada was, and is, a small market compared to the US and it just was not economical to build two different engine sizes here. Chrysler started an engine plant here in 1938 and hence the difference since then.

Edited October 16, 2013 by RobertKB

[54Illinois]

Thanks for all the info...I forgot about the block size, and that would sum it all up.

[pyrodork]

A 25 inch Desoto engine will fit in a Plymouth but not exactly a bolt in. Most external bolt on parts are the same such as water pump, fuel pump, starter, generator, etc.

don,

i'm looking at a 25" dodge truck engine for my 37 plymouth sedan. i know the radiator needs to be moved forward, but is there anything else? do you have any photos of how you adapted your car to fit the engine? if i move my radiator forward, the filler cap is inaccessible. would a later model radiator fit the space better and still give sufficient cooling?

[Don Coatney]

I believe the hood on your 37 Plymouth (butterfly?) is different than the alligator hood on my P-15. I did not have any issues with the fill cap when I  moved my radiator 2" forward. I did have to modify my front cross member as pictured below to accommodate the harmonic balancer. I do not know what combination of parts you will be using such as bell housing, flywheel, ETC. So my best advice is to measure carefully and mock everything as many times as is necessary to insure success. You can visit my Photobucket albums linked in my signature line below for many photos.