Updated this to reduce the size of the filler neck and free up the mounting location for an oil catch can. If you wanted to make the v1 neck the info is still there wrapped with "spoiler" buttons.
v2 Filler Neck:
The v2 neck is much simpler, smaller, and frees up the airbox mount for use with something else (like an oil catch can or something). It consists completely of a 3/4" barb with female 3/4" NPT theaded end and a 3/4" NPT plug. Drill a small hole in the plug for venting.
Here is the v2 neck (smaller) in comparison to the v1.
Make a bracket.. needs to be a little larger to clear the rubber sealing trim for the hood (will be obvious in installed pic):
Bracket installed:
Filler in place - I just ziptied it to the bracket to hold it in place:
