The primary problem will be the position of the water pump. 55-up engines have the pump about 3 inches lower on the block and further forward which creates fan clearance problems. There is a conversion adapter available which allows you to mount a 216/early 235 water pump to the later engine that repositions the fan properly. It requires drilling and tapping two holes into the later model block, but that's not difficult to do.

The 54 bellhousing is a bolt-up swap, and the front timing plate can be drilled for the earlier mount if necessary.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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