It should bolt up. Heads are a bit (3/4") taller on the 345 because the block deck is taller. It raises the exhaust manifold location the same amount so expect to header collector tubes that same amount.
Depending on what the 345 comes out of the oil pan will need to be swapped over. If the 345 is already a double sump deal you should be ok there.
See that you have room between the valve covers and the fire wall for the extra height of the 345.