My video what I did today.
Thanks to @TheRock for pointing what needed to be done.
This Billet Cap does not have the bevel required to seat into the engine. So here is how I created a bevel to allow it to sit into the slingshot.
You can find it here : SUPERCHARGED CNC BILLET ENGINE OIL FILLER CAP FOR CHEVY LS1 LS2 LS3 LS6 RED | eBay