we had Delta valves installed 3 years ago and had no changes made. I was also worried about the few extra feet of coke from the inlet to the Delta valve but have had no problems with it. Our pilot bit removes all the coke that is there. The only thing I see different is not having a hole all the way to the bottom of drum for the water to drain out. We have plugged the drain line with coke, but this was because operaters left the drain valve open while cutting and did not flush drain line when finished with cut, a practice we do prior to air freeing the drum to keep the drain line from plugging. This is a costly setback, having to get a line mole from the bottom of drain line to the plug.