72 Dart 360 PVC valve issues

Lets not bring up Blow-by just yet lol.

I'll get a clamp tomorrow and see what happens. Like i said when i take the valve off and stick just the hose end (i know its not a good thing) it stops.But with the valve in it doesnt do much of anything. Is there a after market valve that might be better to use than just the plastic ones?
there are metal ones... but usually the plastic work ok too