My 1989 351 Windsor has developed a problem with oil coming up through the PCV valve and breather. It is to the point that oil pools in the air cleaner and drips out onto my headers when the engine is under any load. I believe this may be caused by excessive blow-by, but when I put my hand over the valve cover opening with the engine running, there is not much air movement. However, I suspect it could get much worse with the engine hot and at higher rpm.
That I would have enough blow-by to force oil up through the PCV valve and breather and not burn blue through the exhaust doesn't make sense to me, but what else could it be?
A friend suggested trying a different weight of oil to see if that could fix the problem.
Any advice on this would be appreciated.