Fluid drive swap

[41 p12]

I have a 1941 p12 that I am currently working on rebuilding, its originally a 201 ci flathead 6 with a three speed, my question is will a fluid drive trans bolt up to the original engine and if so what does this swap consist of. The new trans is out of a 1950 Chrysler windsor 

[greg g]

The short answer is no.  Fluid drive components are heavier and longer in length than Plymouth non FD components.  The crankshaft flange on fluid drive is thicker and has 8 bolts connecting the flywheel. Could you swap in the entire fluid drive engine and trans maybe but there would be a lot of work involved.  The best way to get a fluid drive car is to buy one that has it. The long answer is anything is possible with time, money, talent and tools.

[wayfarer]

I agree with Greg, not a good idea. If you want an FD package then find a 230-251-264 with one and swap it all.

[9 foot box]

   The Chrysler transmission has long pinion/input shaft, to go through the clutch and fluid coupling. If the bolt pattern on your P12 bellhousing is the same as the 50’s transmission, you need to change the pinion to the shorter 853864. I have a 52 Dodge overdrive in my 46 P15 that was in a fluid drive. I rebuilt my transmission with the shorter shaft and changed second gear and countershaft for what is described as a fast second. Those parts are in a 1940 Dodge, it changes a stock 25 tooth second gear to 23 tooth and a stock 23 tooth countershaft to 25 tooth. I don’t have numbers for those parts at this time. A Google search came up with a 2013 post by Jim Yergin on this forum. He had to adapt the linkage a bit and get a longer speedometer cable. If you have the 41 transmission, I would swap shift levers on the transmissions, if you can. I think it could work, if you change the pinion.