hey fourty i have had experience with carbs icing up but when its cold real cold 30 below cold . when the truck stops on ya and you open the hood is the carb literaly icy looking? like a beer mug thas been in the freezer and taken out and actually is icy on the outside. if not i would say not iced up.
water in fuel does funny things also but not till usally around - 10 celcuis 20 f
a v8 makes a lot of heat and can keep a carb pretty ice free
when it quits is there fuel in the car,when you open the ail cleraner and pump the car can you see the accelerator pump put fuel in the engine.
if so problably not fuel.
could be ignition, my dad had a 76 for pickup with a 390 and for the longest time the truck would just quit and sit had fuel but spark went away until it cooled down.
changing the ign module worked but it was weird cause you could switch it back later on and it would run fin and sometime for many miles no problems.