I have had an L978 type injection system on my engine for a long time now, and for years have suffered with what is excessive oil sucking through the PCV valve in the driver's cover, which IS baffled, and even screened....and up through the hose to the intake....NOW the first place was in the main vacuum port of the T-body..same 3/8 port as stock, then tired of the problem, I tried drilling a hole in bottom of the plenum when it was apart, and routing the hose there....still oiling....as evidenced on the valve covers around both sides, the driver's valve, and the breather to the ported vacuum on the pass side....
and even past the gaskets on the lower part of the runners on the pass side, oil sitting on the intake manifold near the exhaust crossover....

SO when working on an '86 the last month or so, I did notice in the rebuilding of the top end, that the routing was differant...there was a fitting under the middle of the driver's side between the runners and going directly into the intake manifold....and that is routed to each runner with about 1/8 inch holes in the bottom of each passageway to each individual cylinder....

SO just in a desperate experiment, about 2 weeks ago I re routed that damn PCV hose yet again.....ok so suck the oil directly into the passages down lo and never filthy up the engine top again...wonderful....no sweat idea....

BUT, NOW...the valve covers are CLEAN and without oil.....

WHY????

GENE