I had the same problem, but mine was excessive. I had breather on each valve cover, as well as the oil fill tube. I tried everyting. Remote catch cans off each valve cover and even went as far as adding a vacuum pump. Well, one day I drove the car out to the machine shop to get the crank mandrel machined and fab up some brackets to hold the pump. We got everything machined and installed, but I forgot to bring the hoses to connect everything together, so I was going to just leave everything the way it was until I got home to complete the setup. The machinist, Watt, was puzzled at how much oil was coming out of the oil fill tube so we did a few thing to try and figure out where the oil was coming from. I mean come on, there isn't that much pressure to push out over a quart of oil on a 30 minute drive! so we took the breather off the oil fill tube and I started the engine. Watt put his hand lightly over the tube and had me rev it up. Well, I went to 6000 rpm and he didn't even get a drop of oil on his hand. We sat there and stared at it for a about an hour and couldn't figure it out. How in the heck was the oil coming out of the fill tube???!!!!! We looked at everything we could to try and figure it out and that's when I thought about the breather I had on the fill tube....It was a K&N breather and that's when it hit me. The fill tube is directly behind the fan and is tilted at an angle....Well, guess what happens when you have alot of air rushing over an open hole...That's right, it creates a vacuum! I pushed the breather all the way down to seal up the tube. I still had the breathers in the valve covers. Watt told me to drive it like I stole it on the way home to see if there is enough base pressure to push the filter up (it would slide up with little effort) even with the valve cover breathers in place.. We were still thinking base pressure as the problem as well as my theory of the vacuum effect at this time. Well, I drove the snot out of it, pegged the speedo for at least 15 minutes straight and when I got home, not a drop of oil anywhere and the breather was still pushed down tight to the fill tube. Since I had already gone through the expense of purchasing and installing the vacuum pump I went ahead and completed the install and put a rubber freeze p[lug in the oil fill tube. I haven't had a problem ever since.
So, plug the oil fill tube or use a stock style breather and put in some valve cover breathers or use a PCV setup.
Pressure probably ain't good in the long run. Finally got her back on the road?
Dave which valve covers are you using? If at all possible some kind of PCV system will be worth 5 fo 8 HP.
