If you drill through the center of the sprocket nose you will gain an extra four inches of cutting space, don't be worried to do this because nearly all have a large solid bush at around a inch or more in the middle of the rollers inside,
You can drill the bar using an ordinary masonary drill which has been re-ground to 20 degrees or so, drill the pilot hole half the size of the finished hole, or you won't get a neat hole, drill hole to 5/16" for the nose and 3/8" for the other end, when you start drilling don't stop until you are right through, or the metal will work harden and make drilling more difficult, I us cobalt glass drills which cut through like butter.
For a 395 the most effective cutting width for the saw to weight ratio, is a width of no more than 36 inches any more and the fuel consumption will go up and strain upon the saw will wear things out faster than it should.