318 4" bore 3.58" stroke(360)

RustyRatRod said
Hensley Motorsports has been hoggin out 318s to 4 plus inches for thirty years. They don't hard block anything.

Thats right, and so have i, half that long though.
No need to block fill unless you plan on turning rpm's higher than that crank will handle to begin with.
Where are all those nay sayers now? ;)