Set up properly the PCV lowers the crankcase pressure a slight bit, nothing like the vacuum pumps though. A resulting side benefit is reduced oil leaks since the crankcase pressure is below atmospheric.

I think it will work at basically manifold pressure,
and yes my front seal has stopped its weeping.

I tried it because I was unsure of vacuum leaks and EFI tuning issues I was having, but if it's going to cause long term issues I will change it back. It's still however able to pull through the dipstick.

Roger, perhaps I worded that poorly. The Offy I had years ago had two openings under the center carb, that then somehow connected to the runners to the valves. I never cut one open to see how it worked. I was told the Edelbrock's went straight to the runners, but I never owned one. Long time ago, and getting OT.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

if the front seal quit leaking, now you are moste likley sucking dirt into the crank case threw the seal,as it is desighned tohave some presure in crank case,as well as inhibiting oil drain back. you should not havea vacume in the cranke case. ideal would be a minor amount of crank presure. just studey modern pcv equiped withpcv. they all have access for air to enter and stop vacume 

Here are a couple of links to past threads regarding PCV systems.  Using the search function will bring up a bunch more.
Crankcase evacuation
Why a PCV valve or system? 

Lorena, Texas (South of Waco)