These discussions lead me to see if my local AC Delco store still had any "purple" CV746C PCV valves left. It was my lucky day; they had one left collecting dust for $4.08.
The purple valve on the right is P/N-6484525, made by AC Spark Plug. The one on the left was noted as a std. issue replacement for SB Chevy, P/N-6423695, made by AC Rochester, which is a CV736C.
Hopefully some can confirm this, but it appears the PCV’s are "calibrated" with a coded, internal weighted check valve to work with specific engines based on their vacuum draw, etc. The CV746C is coded with a "K" check valve, the CV736C with an "M". See attached pic's.
The 1969 Camaro AIM calls for:
P473, UPC Z28, PCV P/N-6484699
P101, UPC C8 covering the std. V-8, PCV P/N-6484541
P281, UPC A7 covering the 396 V-8, PCV P/N- none given, and states "Production Part"
P94, UPC C1 covering the L-6, PCV-6424191.
The "purple" valve sold on eBay recently, listed the CV746C fitting:
68-69 Camaro (302)
70-71 Camaro w/special high performance (350)
69 Corvette (427) w/430 HP
70 Corvette (350) w/350 HP, (454) w/425 HP
71-72 Corvette (350) w/330 HP LT1, (454) w/465HP
73 Corvette, Camaro w/HP (350).
Can any one confirm the K vs. M coding and the application for the CV746C?