Purdy. He did the air tubes the same way I do mine, copper tubing. I don't polish so pretty though. I think the bump/ridge was to help get the air tumbling in the intake. There are enough turns and curves before the valves that I don't think it was necessary. Some people cut the front side of the rod off to help flow but I am afraid it would lead to a twisted butterfly. "twisted butterfly" sounds like some kind of new-age rock band.