No on the bell housing pattern, for the most part. There is a bell the 60's trucks used that incorporated the rear motor mounts that had both patterns. It was for the NP435 truck 4 speed (granny first).
I also have a very vague recollection of a factory adapter plate that allowed the SB bell on a /6 in 60's vans.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.