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

...It's hard to do an apples to apples comparison, Eg.. Mainly what were talking about 318/340/360 vs there 4" stroke version, but what is an apples to apples comparison between a 365 vs 408?...

Exactly. And that's why nobody outside of competitive racing teams are doing that. It's too much time and money and effort to do that, when that same time money and effort could be applied to big picture things.