It sounds like you have blow-by. This is from worn out piston rings.

To check for sure, put your hand over the oil filler cap while you rev the engine. If significant air is being forced out, that is from the combustion of the cylinders coming past the pistons and into the case. There will be some pulsing of air but should not be a significant force.

This will shoot oil out the cap and breather no matter how nice your seal is.