Will a crankshaft from a 1977 305 Chevy block work in a 1974 350 Chevy block?

It will fit, but you might want to have the crank, rods, and pistons balanced first as there is a big difference in the weight of a 350 piston versus a 305 piston. Wouldn't want to get it all together and have a nasty vibration at certain speeds.