In California, the PCV has to plumb back into the intake after the throttle bodie(s), for cars registered through SB100.
I printed test pieces in PETG (FDM process) before kicking the design up to Xometry to print in Nylon-12. (SLS process) SLS nylon should be durable/heat resistant enough. The price per piece is shockingly reasonable.
The .STL for these injector plug vacuum nipples is available from my feed at Thingiverse. (Offered under Creative Commons Attribution-NonCommercial-ShareAlike license.)