340 Vs 360 which is better?

340 and 360 have 4" bores the 318 has a smaller bore.The 340 has a shorter stroke same as the 318 so if one was to stroke a 340 and 360 with the same crank it would be the same cubes.

Not exactly, the 340 has a 4.04 bore. The 360 is a 4.00