Usually this is a bolt in swap.
I swapped a 301 out of a '79 Firebird and replaced it with a 400 chevy. For whatever reason the passenger side of the crossmember was drilled for chevy motor mounts and the drivers side was not.
Do as suggested, bolt the upper and lower motor mounts to the block and lower the engine into the car. If the appropriate holes are there, its a bolt in deal. Otherwise, scribe the location carefully and drill new holes.