Primarily the bore size. The 305 has a bore of 3.74 and the 350 is a 4.0 bore. They share the same stroke on the crank. And no, you can't bore a 305 to a 4.0 bore.
yes
1976
clockwise
No. There isn't enough material in a 305 to bore that far oversize without hitting water.
90mm
Chevy-GM 5.0 liter is 305 CID.
No
3.48 inches.
Subtract 305 from 350 and that will give you the difference (or interval) between the two numbers:- the answer is 45. However, if you mean what is the difference between a Chevy 305 and a Chevy 350, then it is the difference between the engine bore (the cylinder) sizes. The 305 bore is 3.740 inches. And the 350 bore is 4.000 inches, giving the Chevy 350 20HP more then the Chevy 305.
A 305 chevy engine has a bore diameter of 3.736". Check the diameter of your L2256 piston to see if it is that size.
A Chevrolet V8 engine with 3.736" bore and 3.48" stroke and tuned port injection.