Very interesting
I dont know how that system is going to circulate gases out of the crankcase without a breather in the system. That's probably why you are seeing such high cc vacuum.
Good luck, report back after some mileage.
Crankcase vacuum is supposed to create good ring seal.
You dont use breathers with pan evac system either , usually one hooked to each valve cover /no breathers..they empty the crankcase gasses , much like the pcv system is doing, the trick is will it do it at all rpms.-----???
I know of gm guys running totally sealed systems on street cars.