Why does the tab need to be ground off?
There is no need to turn the adapter 90 deg to get it to lock, if you do the opening is sideways (pointing to the back of the car).
You only need to push it into the OE filler on the valve cover and then connect the Motive MX2302 funnel.
https://www.motivxtools.com/products...2&_ss=e&_v=1.0
Did I miss something?