What will cause my float bowls to go dry

Swinger 340 said
Why not just add the fuel to the air horn, that way no spillage. I also have the same problem with my AVS on my 340 dart. I just rebuilt the carb and thought it would help, not. I'm kind of leaning toward the check valve because when I removed the fuel line from the carb, there was no spillage. As in plumbing (water) check valves do go bad. Never thought of that, Thanks.

I'm sure the ease of the process depends on the carb itself. My AVS is an emissions carb, and has a vent valve. Just push on the linkage and put in the funnel. Vent tubes on Holleys could be the fill point. The last time I ran a Holley it was on my daily driver and you could still get leaded gas!