Jerry,

How will a 216 clutch housing (bell housing) work in a 1955 truck?

The clutch housing has a different angle for the rear motor mounts. And, because the motor mounts are in a different location, the 47-53 rear motor mounts are a different design relative to the 54-84 rear motor mounts.

The shape of the rear motor-mount frame cross-member changed in 1954 (that is why no frame cross-member and transmission mount was needed after 1954 for manual transmissions).

Yes, of course a 6v or 12v clutch assembly should be used, depending on which is intended to be used in the 1955 truck