Is building a stroked 318 better than a stroked 340/360?

To me the point of a 4" stroker is to build displacement don't know why you'd start with less than a 360 block for the slight extra that it would cost especially if you factor in piston cost like J Par said, but saying that a 390 still will work good, just makes going stroker make less sense especially this isn't a low dollar build why cheap out on block. 365 vs 390 vs 408 a 390 is slightly over half (25 cid) of the displacement 43 cid gain between 365 & 408.