Physically Impossible

My 76 Pontiac Ventura (40k original mile Oldsmobile 260 V8 with a Dualjet carb) needs to be pumped multiple times unless it's being driven daily. My wife is always worried that she will flood it, never happens though. I pump it several times before I start cranking, then while it cranks. Usually it will fire up after about 15 seconds of cranking, then stall after about 5 seconds, 2 more pumps and good to go. When it's being run daily, 1-2 pumps and fires right up. My Dart has been really good no matter how long it sits, 2-3 pumps and fires quickly, running an Edelbrock AVS2 with electric choke.