I know differences existed in the war time engines but what about the other years such as does a 1937 engine fit in a 1941 Cadillac?
I installed a 41 engine in my 39 and had to do some grinding in the area of the starter on the block. My starter mounts lower in the bell housing, and bolts pretty much vertically.(12-6) The 41 bolt pattern seems to be rotated somewhat inward toward block.(11-5) The block needed to be clearance to be able to get the lower bolt in. Not much involved. Plus I think the starter solenoid might be mounted slightly rotated to avoid hitting block. The bell housing on my car has a pivot for the clutch bell crank so I had to us it instead of the 41. It was doable however. Not sure about 37. I think I would check MPL to see if you bell housing is the same as my 75 series. My 41 engine was a series 62 IIRC. Food for thought.
Yes Gary, it can be done with a little work, 37 on.