CV 746 C PCV valve differences

[bergy]

I've been using these - same style with no shoulder.

[Salvatore]

The 691's are easier to find then the 746's it seem Bruce.
Cheaper too!

[Steve Shauger]

Great topic and interesting thread. I believe like you Chris, that the flat top /spun type was 1969 production. Also I have seen the stamped raise on two late Oct 69 survivors but they may have been changed. The middle machined /raised is one I've not seen or am familiar with, but there may have been a transition period. I'll check some pictures I've take of cats built in that time period.