340 Vs 360

360 has a 4.00 bore std, 340 is 4.040 std. 360 has a 3.58 stroke, 340 is 3.31. The 360 is also a cast crank engine, 340 can be steel, or cast. 360 main bearings are larger. Motor mounts are interchangeable. Oil pan is not, it is 360 specific. For a mild street engine, either one is capable of great performance. The 340 will allways have the reputation though, and usally more resale value..