FiTech EFI system

Well you have two bandaid esque issues there.
1. The vent shouldn't be blocked off...but I suppose if it isnt vapor locking already...then its functioning as is, so it may be able to be used...i guess. Its Probably Venting through the neck.
2. In line pumps are not designed for, or good at, pulling fuel up hill. (Oe sending unit)

The correct way to do it is..
Command center with oe pump
Sump the tank with inline pump
Fuel cell with inline pump
In tank fuel pump

Nothing else is "correct"

If you are spending a G on an efi unit...the hundred bucks to upgrade from the frame rail pump kit to the command center or a sump is a fairly silly skimping in the scheme of things