Very cheap and easy fix,,, install an electric fuel pump, keeping the new mechanical pump. It's cheap insurance if the mechanical pump fails, you aren't stranded. Be sure to wire it to the hot side of the ignition key, so you don't forget and leave it on. Let it run 2-4 seconds before starting, and it'll fire right up. I've had an electric pump on all my (many) Mopars...
Monkey, pilot of a Great Dane hauler,
2015 Silverado 2500 Duramax/Alison 4x4 CrewCab 2016 Cougar 28SGS