the crankcase vent nipple needs to be open to the atmosphere, as bhole said. Your engine will probably run ok, but the problem will be when you are trying to fly inverted. When inverted, your tank will be one inch HIGHER than your carb--therefore, fuel will siphon rapidly into the carb, and flood the enigne out. you will have all sorts of headaches until you get it right. I don't understand what you mean by "foul out the nose gear." How does the placement of the cylinder head affect the nose gear?