1st check the pushrod as mentioned above, but if it was a pain to install then it was likely arleady pushing out. You can take it back off though and turn the engine (by hand) and the rod will change position
2nd pull the line that goes to the tank (AT THE FUEL PUMP) and put it directly in a jug of gas. Then, pull the line from the carb and see if gas goes from jug to line to carb. It should, if not, change fuel pump again. If it does, then put the line back on the carb. Turn over again, fuel will go into carb and the truck will start. If this happens, then you may have a kink in the gas line, or a large bit of trash or broken tube inside the tank (depending how gas is siphoned into fuel line) but either way the problem would be somewhere from the pump to the tank
Also, it takes quite a bit of turning to get fuel up to the carb sometimes. Maybe you just need to turn it over more?