The cline uses a check valve and is tapped into the back cover I had my tank 2 feet back just to test it I ran it for a few minutes shut it down and pulled tube of the regulator it shot fuel a good 10 feet
crankcase pressure can be as high as 9 lbs thats like YS pump pressure
the best thing about the cline is no chance of flooding inverted engines like the perry will do if the tank is too high which is the case in lots of inverted engines