I have a 3/8" inline check valve used on F-series fuel lines to prevent tank-to-tank siphoning. Its basically a male/female quick connect based on the SAE J2044 endform design. Can it be of use to you? Requires approx. 1 psi to open the valve. Check Valve Devon
Yep! F3TA-9J274-BA If you can't find one let me know, I may be able to part with this sample but I'm not sure. Devon