Yar, I use 1/4" lines.
I raised it out of concern that the suction would pick up oil splatter if it sat down too low in the crankcase. I can't say that I had a problem when I had it mounted in a freeze plug directly in the draft tube hole, but I was concerned that it would suck up oil. I raised it to avoid that.
Something that you might want to consider is to fill the vents on the valve cover, then add a fitting to the valve cover and one to the top of the air cleaner. Connect the fittings with a rubber tube. That will allow the engine to breathe clean air that has been filtered through the air cleaner.
If you want to keep the vents looking cosmetically the same (but closed), I remember reading a post on this forum that someone had filled the openings with JB Weld, then sanded them smooth. I thought that was a good idea when I read it. I seem to recall that others have filled the gaps with silicon. I have seen several conversions with the vents pounded closed and then brazed shut.
Matt
