1971 Plymouth Scamp ECS fuel tank vent
as cast the mopar performance valve covers also dont have a filler hole, do they?
if your intent is to keep the evap system (and you should have a PCV system set up anyway) i would suggest taking the new valve cover, drilling the proper sized hole and installing the stock collector
of course, that is just one way to go about it
and welcome aboard, from the lakeshore