People hear 340 and think of days of old when men were men and 340's were the rulers of the small block world. It has street creds as they say today.

But 360's are cheaper and more cubes mean more power potential. Aside from the cubes they are the same engine. There are differences like head casting numbers and cast/forged cranks and bearing sizes etc but nothing that would make one a better engine in your case except the cubes. It's not like a 440 and Hemi where the block is the almost the same but the heads are radially different.

If you want to impress the old farts who wax nostalgic for the good old days then get a 340. Otherwise get the 360 for the cost and the extra cubes.

Heck get a 360 and put 340 on the Air Cleaner