Even a bad PCVvalve would likely not let that much oil into the intake. Your PCV (positive crankcase ventillation valve) relieves pressure that can build up inside the crankcase (the head space above the oil in an engine, passages go all the way up to the heads). A line is run from that chamber to the intake. Any pressure build up is relieved into the intake and burned with the air/fuel charge.Some older cars just vent ithe crankcaseinto the engine compartment but it smells like oil and can be dangerous (flammable).
What is interesting is the timing of this whole thing. You didn't have this problem until you overfilled your engine with oil. When you do overfill, your engine does not burn off the excess. Excess oil doesn't just get burned, in a good engine it just stays in there. If you overfill your oil reservoir too much, it is possible to actually lose oil pressure in your engine. If you lost oil pressure because of the overfill then you could have done engine damage that would result in your engine burning oil. Also, valve guide seals don't normally just go out all of a sudden. They usually go out over time. <o
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The first thing I would do is a compression check on all cylinders.