as seen as the question is somewhat open ended.. with way to many being anal about it..
most chevy 350's don't have forged factory piston, nor do they have forged cranks..
so to answer the question in the way I take the o/p asking it..
if you go grab a 350 out of a junkyard and bolt it in, without rebuilding it.. changine the cam.. and adding headers/etc..
most will make 350hp without blinking,, cast crank and pistons,2 bolt mains.. thats going off the millions of engines out there and the most likely one you'll come across..
even if the one you find has forged everything and 4 bolt mains, it don't mean anything.. it might give up way before a cast piston/crank one will. like anything it's the luck of the draw..
I beat the living crap out of a 100k 350 with cast crank/pistons/2bolt mains.. and had no problems,,
I've had low miles truck engines(forged crank/4 bolt mains) spin a bearing..
but figure you're pretty safe with any 350 handle'n 350hp no matter whats in it.. as long as it's healthy..
cast parts don't like shocks, so if you dump a clutch at 5500rpm you might find the crank on the ground..
cast pistons and happy gas isn't a good idea either.. as you have to be dead on.. with the tune..
having said that.. I sprayed the crap out of a pontiac 326 cast crank/rods/pistons.. for a good 2 years..
but thats was more of being lucker than good..