Technical Plymouth flat 6 question

I'm the proud owner of a 1941 Plymouth with a cracked cylinder head (952083-2). I have a spare one (1120803-5) which from my research is 1942-54 Plymouth. Will these parts interchange straight across without any issues or is there a heads up I should be aware of? Any help is appreciated, thanks.

 

First of all , I am no expert. I have been doing a lot of research and reading on these old engines.
Somewhere between 34 and 35 they changed the starter location and you need correct starter and bell housing to make a swap work.
Somewhere I watched a youtube video where it showed you the difference in years in the cooling system. Was some sort of internal bulge and was related to the water pump or the T-stat housing I cant find it now, but sure it is not head related.
I have 4 mopar flathead sixes, 1 is in my truck and a 1937, and 3 are early 50's and you cant tell them apart. Mopar used the same engine with little to no changes for years and years.
Someone will set me straight, but I think you will not have any issues with the newer head.

Edit: Cough, I am speaking about the 218 mopar 6, and the 23" block, of course the 25" blocks the heads wont interchange. But even the 23" blocks the difference in the cubes was the rotating assembly and not the heads.

 

It's "flathead". Calling them a flat engine stamps you as a noob.

They used basically the same engine from 1937 to 1959 in Plymouth and Dodge cars and Dodge trucks. In late 37 they changed the block to make the water jackets go all the way down the cylinders but the heads are the same.

Second, there should be no problem interchanging the heads. Some heads had a square bulge at the front for the water pump but this is obvious. If the heads look the same and the bolt pattern is the same they are the same. The newer head may have slightly more compression which is all to the good.

 

Before you catch a lot of grief, it is a flat HEAD six. Corvairs, Subarus, Porsches, etc., have flat sixes

 

your enigin is a 201 has a slightly smaller bore, than the 218 from later years so you may need to use the later head gasket with the later head. This assumes both engine blocks are 23 inches long.