318 or 360?

If you are spending the $$ for a rebuild, yes 360 makes some sense. Or get a magnum 5.9 that needs no boring and still spend dollars.
If you find a good running engine worth the $ I would not hesitate for the 318. Lets say there is a difference between an early higher compression 318 and it smogger brother.
Just like gears, long legged 2:94 vs 3:55 Makes a difference.