Since little to no information on our sixes really exist, I find that factory/GM promotional shots and ads are a great source.
This early hood-less 1966 Sprint engine images is one I've always admired and somewhat used as a guide to detailing.
If you examine this photo you will notice lots of neat little details the black AC breather is one;
While freshening up the bay I will on occasion look around the web for detail info and items.
Before I blasted the shininess off this re-pop cap I considered looking for a possible NOS and
had mentioned how sometimes the prices exceed reality well this one takes my thoughts on this to a new level...
https://www.ebay.com/itm/NOS-AC-FB-8...19.m1438.l2649
I'll stick with my faux recreation
__________________
When I die, I want to go peacefully like my grandfather did, in his sleep.
Not screaming like the passengers in his car.