I had the same thing happen to me . Any boost approaching
15 #'s would spit a valve cover breather out or puke oil out
of the dip stick tube. When I switched to Champion heads
I also had to change the valve covers. I'am currently using the
tall cast aluminum GN1 valve covers with a tall K&N breather
in each valve cover. Problem solved. This should work for you.
Good Luck .
Best ET to date on 93 unleaded
10.78 @127 MPH
20 # BOOST