Many years ago GM released a PCV valve to solve the low vacuum issues on their high performance engines in the 1960's.
It is a fixed orifice PCV
valve. It has a small hole in the bottom that regulates vacuum at a fixed rate.
The part number for this PCV valve is GM
part number 12572717 and you’ve probably seen this referenced all over the
internet while doing your search for oil control issues and low vacuum
problems.
GM part number 12572717 has been obsolete for a number of
years now. This PVC valve is an aftermarket reproduction of that same PCV
valve.
The body id 3/4" diameter 3/4" long to the seat. The
other end is sized for 3/8" hose. The overall length is 1 5/8".