Help us out a little more. What do you want to accomplish with this change? Do you plan to stay with the original motor?
You're dealing with stuff that is earlier than where I feel confident I can offer solutions. What I can tell you is that the bellhousing on a '41 1/2-ton, and I presume also a '41 3/4-ton, is different that the '48 and later stuff.
The transmission bolt pattern is different, and the bellhousing has a support that has something to do with the clutch pedal. But if you are changing motors too, that kind of information can become irrelevant.
What are you trying to accomplish?