My dad's S10 w/350 SB did the same thing see T.Jerman's post that's how I fixed his as well,with splash plate.It would suck out all the oil he couldn't figure it out for the longest time he just thought it burned oil.The new valve covers had no baffle to stop the oil from being sucked up through the PCV.This is the reason my engine builder didn't want to use a hi-vol. pump, he said excessive pressure could cause leaks. I can't keep oil in this motor, but it's not because of leaks. I'm still fighting the problem of oil blowing out through the valve cover breather. I have a new PCV valve in one valve cover and a breather in the other and whenever the engine sees higher rpms it blows oil out through the breather. I put a new grommet in the valve cover under the breather with just a narrow slit in it but the oil still blows through. It's been frustrating.