I've got a BB 468 full roller making 550 or so, it was professionally built about 2000 miles ago and I've been using 20W50 Penn Grade green oil. The prior owner used only Rotella. I have a 10 quart oil pan so there's quite a lot of it, no racing, I do cruises only with it. When I drain the oil after a summer's cruise season, that oil is BLACK. Even if I change it and check it soon after, its black already. Not sure if this is normal, I've heard one say not normal. Could it be due to the motor breaking in? I did a fresh rebuild on the Demon 850, so it shouldn't be flooding although my exhaust fumes are noxious and I get about 6-8 mpg. Any comments?