<VV> Choke Pull Off Info Request

[Grant]

It has recently come to my attention that there are some plastic Rochester carburetor choke canisters/pull-offs in circulation that are causing problems.
Some have been tested and require as little as 3 psi to close, while some causing a problem can take as much as 15, so they just don't open when they
should, if at all. The problem ones seem to be the after-market two-part ones with metal bases. So...I am checking to see if someone out here knows what
the "factory spec" should be for Corvairs? It is determined by the size of the spring inside and the thickness of the diaphragm. Thanks for any insight.
Grant