I think the 1958 front motor mount would be OK.

The rear "motor mounts" are on the clutch housing. Use the clutch housing and clutch assembly and rear motor mounts from your 1947 car. Use your 1947 6v starter.

Your will have to use a water pump relocation plate and your 216 water pump for proper cooling of the radiator:
http://chev235guy.blogspot.com/search/label/Water%20Pump%20Relocation%20Adapter