https://www.amazon.com/dp/B01KHLJPZ2...v_ov_lig_dp_it
A member here typed that he installed this on a Thor, but I don't remember if a cutaway or bare chassis, and he didn't post a pic that I remember.
Anyway... If this fits a bare chassis, it's on sale for 30 bucks and that's pretty close to the cost of making the pvc kinda wonky oil fill adapter people make... And this one doesn't need stored somewhere.
I am taking a different path on oil fill. Someone should buy this and post and install thread.