Had a '51 CJ3A growing up at home... planned on putting a 289 in it... wish I could remember, but there was an outfit that made a custom bell housing that would bolt it right to the stock transmission!! Ended up scrapping the idea because I was in high school at the time and had no money.
A buddy had a high-hood and put a 302 in his. His biggest obstacle was routing the left exhaust... he ended up putting a crossover in front of the engine to make it work. The stock steering gear/column was in the way. My '51 had the steering column and gear from a '64 Ford galaxie in it... very neat and would have been easy to route exhaust by it.
Sorry I can't remember the name of the outfit that manufactured the bell housing assembly... if I remember, I'll send you a note.
Loren