Is It The Fuel Pump?

Honestly it sounds like most of your stalls were going uphill. What's the float level set at?

The other thing is, carbed engines need to warm up. If it sits for 4 hours and cools off and you just punch it from stopped you're probably not up to temperature. Obviously some combinations are more "cold blooded" than others, and it depends on your timing settings, carb tuning etc. But until the engine is up to temp you're not going to get full performance, it's not fuel injection. What kind of choke do you have on the car?