What do you think about this 318 guys.

It does make little sense to build less than the biggest bore available. 340 if cheap and plentiful would be obvious choice but since it ain't 360 makes the most sense, but really for the power levels most are shooting for a 318 bore can do it even a 273 could handle 400+hp should you?
It's a bit of a sacrifice but obviously a 3.91-3.97+ bore can make power but that's up to owner if that an acceptable sacrifice for really little reason to do it over a 360? But then again if you want bore size the 4.25-4.34 of 383/400/440 is readily available and people choose the 4in over them high percentage of the time :)