[Berg]

Hank is correct on the water pump pulley and accessories fitting. The motor mounts are even the same but you'll want at least a 3 core radiator unless you run an all welded aluminum one. The throttle cable will need to be changed too and you'll need a bracket that holds the cable. The thermostat housing will work and you can swap your smallblock sending units over for the oil pressure and water temp. Battery cables and heater hoses are OK too but you'll need a new set of upper and lower radiator hoses. Remember when upgrading to a bigger radiator you may also need a new top plate. The only pulley you will need to purchase is a crankshaft pulley. If you are reusing your accessories and their original pulleys you'll want the non-special hi-performance pulley for a long water pump setup. The fan shroud will also need to be swapped out. There are alternator bracket and power steering bracket kits out there that come with everything needed to drop a big block in your ride. FYI try to find original GM stuff. The aftermarket ones line up like crap sometimes. Some suppliers actually have stuff right from GM and some dealers can still get most of them since they were used for many years on trucks with big blocks. You could always do the junkyard thing too.
Shadow Gray is right about the suffix code. It will tell you what it came in and even though it is stamped Pass Hi-perf it could still be an engine out of a pickup truck. It just means it isn't a tall-deck (in most cases).