If it was a Holley I'd say almost for sure it's float level related (certainly fuel related I suspect). But an Edelbrock? Hmmm, got me there!
It seems Holleys are notorius for needing yet 'another' adjustment on the float level. Thats why they made it so easy to adjust, 'cause they NEEDED to!
But most other carbs float level adjustment is more of a 'set it and forget it' type of thing. If anything the symptoms sound like your 'running out of gas' (that is float level to low).