Cox Engine Tests/reviews ONLY

I would like to make back plates with presure tap but the one way valve is more complex to make I found a part that could possibly replace the valve but I am unsure I imagine that the valve has no restriction as to the direction of flow The one I found has a slight resistance although minimal I believe that the motor would be incapable of countering the spring and succeeds in pressurizing correctly if the spring To hard ...? My question as I have never been able to find a valve or even a back plate with presur tap I would like to know the valve diameter specifications but above all how it works Whether the valve simply has a floating ball or with a spring and a slight resistance to prevent the engine crankcase from becoming completely depressurized ? I would like to find a substitute to replace this part ! Because I would like to carry out tests with small tuned pipes but I cannot use the pressure in the exhaust system so this system would I believe be the only option
I would like to install this cooling jacket exhaust collector on a tee dee with this exhaust system equipped with a restriction valve