First off, while the blocks will interchange in the chassis, pistons will not. The bores are different sizes and you can't make a 305 a 350. The 350 and the 305 share the same stroke, but the 305 and 350 crank throws are balanced differently due to the different weights of the pistons. You theoretically can rebalance either to fit the other, but you are better off just trying to find a 350 crank to start with. 305 heads? Garbage. Good 350 heads should not be used on a 305. The valves hit the bores. As far as it goes, you say it was bored previously. If it was .060 over last time, the block likely can't be rebuilt again so it may not even make a good core. Next up, the reason the bearing failed is that he did not properly start the engine after sitting that long. The bearings were dry and the pump may not have been primed, thus killing the bearings. The crank may or may not be OK, but my money is on not. Your next question will be did a main bearing spin in the block? If so, is the block toast? Did anything else like the cam get damaged from being run dry? Are the cam bearings bad? Is the engine worth it? That all depends on what it has on it. If it's just an Edelbrock intake, so what? If it's Edelbrock heads then it may be worth it. The intake is cheap used so it's not a huge selling point unless the engine is around $100.
