Certainly a good way to add a PVC. Similar to the Y-blocks with the exception of the valve being vertical and in a hole in the valley pan on a Y-block. All you need is a sealed way for the vapors to enter the intake and an adequately sized check valve. I'm old enough to remember following high mileage cars on the highway with smoke coming from the road draft tubes - must have really stunk inside.
I'm wondering, is there any material like coarse steel wool in the underside of that domed area to help filter or condense vapor into
liquid before the fumes enter the intake via the carb or a spacer plate?