Mike
There were many, many combinations of bores and strokes on the Chrysler sixes.
The Canadian wartime 3 7/16 bore engine was 236 cu in not 250 they were produced alongside the 3 3/8 engines all through the war.
I will have a look at the KEW engine or engines to see the stroke/s (they are 3 7/16 bore)
As you say any engine will do but it is nice to have the most power available.
This link has it all.
http://www.t137.com/registry/help/ot.../tengines.html
Lang