I just replace my mechanical fuel pump on my 1996 454 gen 6 motor. I can't get any fuel to the carb. question: after looking at new pump the a rubber plug was left on the fuel vent tube, will this cause no fuel to carb?

no that is if the fuel pump starts leaking it will come out of that tube that if supposed to be connected to your carb...... did you make sure your fuel pump rod is in correctly or in at all???????