Just wanted to report the solution of a problem that took some time to achieve and seems to be quite common.

Scenario: Saito 100 mounted inverted in warbird. Unable to place tank below carb level due to plane construction characteristics.
Issue: Fuel flows by gravity to the carb, flooding the engine that is located below the tank level.
Solution:
1)Add one modified fuel filter right before the carb. This filter works as a gravity valve by adding one ball bearing inside the filter that is fixed upright as seen in the picture. This valve would work better if you force the ball bearing against the bottom of the filter aluminum body to proper match its profile. Just a small hit would make it.

2)Add one fuel filling valve between the tank and the added fuel filter to work as a fuel switch. After searching for something specific without success, I used a regular fuel valve and it worked great. This valve can be used to shut off the fuel flow at anytime when the engine is not running and very useful in those cases where the plane is stored upside down ( that's my case ), since the fuel filter added in step one wouldn't work inverted. Also, I found this valve useful to prime the engine before start.

Hope it help someone.

Thanks,