Gillingham took the lead through Danny Kedwell's far-post header, but Chris Robertson equalised for the home side with a close-range header.
Vale mounted pressure after the interval and it was no surprise when half-time substitute Pope headed home in the 63rd minute.
More top news
The American heavy metal band are the first act to be announced for Reading Festival next August.
The two projects going head-to-head today are Parks for People and Riverside.
The two projects going head-to-head are Assist (Thanet) and Base Camp.