I found this little in line check valve in the Chapperal Motorsports catalog. They call it a Gas Stop 1 way valve that you install in your gas tank vent hose which doesn't let gas spill out of your tank , yet still allows air into your tank so it can vent . I know on my 8.5 gal. tank , I can only put in about 7 to 7.5 gal. before gas starts running out my vent hose so I'm going to give this check valve a try . Just though it was interesting .