Carter AVS on a 340 drains of fuel

Like someone above said today's fuel will evaporate out after the car is shut down. I run my car with the intake manifold heat cross overs blocked off and it helps some. But no matter what I do ALL the fuel is evaporated out after the car sits a few days. Edelbrock makes a carb to intake gasket that is supposed to help with this problem:

Heat Insulator Gaskets
Designed to help prevent fuel percolation in Performer Series and Thunder Series AVS carburetors exposed to extreme underhood temperatures. Use #9265 with open plenum manifolds such as Torker II and Victors. #9266 features a divided center which is designed to seal the carburetor to dual-plane manifolds including Performer, Performer RPM and most RPM Air-Gap manifolds. All gaskets come with extended carb studs.

Square-Bore Heat Insulator Gasket (0.320" thick) #9265
Divided Square-Bore Heat Insulator Gasket (0.320" thick) #9266

http://www.edelbrock.com/automotive_new/mc/carbs_acc/access_thun_perf.shtml