RE: 2 Klunk/Pump Setup
Actually this makes sense if you think about it. The exhaust at WOT is pressurizing the tank to its max pressure but that same exhaust pressure keeps the fuel from blowing back into the vent line and into the exhaust. Then all the sudden you drop the throttle back, there is pressure still in the tank and it can't go in the carb so it flows back to the exhaust for a short period. This is because the vent line is in fuel at the bottom of the tank. There is only one place for the fuel/pressure to go, back to the exhaust. Makes sense to me.