3B and Longbox are giving you the correct procedure/thoughts. "First drive" meaning it has new what? Fuel delivery is checked by undoing center wire on distributor, undoing connection at carb, crank motor and let fuel run into a container to see if it fills pretty fast and has a strong pulsating flow. This is a fuel flow test. If no squirting, work backwards toward tank until you find flow. If flow good at carb. Check built-in carb filter and carb function. Be sure the "big filter" is not clogged.
Check for vacuum leaks, fittings, hoses, pipe plugs missing, loose bolts...
If it ran an hour, could be fuel clog as 3B says or you ran out of gas!!!! Check the tank!!!!!! Put 2 gallons/8 liters in.
We assume the silver device is a fuel pump with two bolts into passenger side front of block? If you don't know what it is, it sounds like you are not experienced with motors or their workings.
Merry Christmas. Keep us informed with history of work done, results and observations of tests, so we can help further.
Looks like you have a 48 3100 with a 350. Holley carb. Nice truck.
