I’ve got a1986 Wheelhorse 416-8 tractor that I bought new, I started it awhile back and it made a funny noise and started blowing oil out the side, still ran good though.I pulled the PTO off and the drive pully and found the shaft seal was lose and spinning, I replaced it and thought I’d check to if something blew first so I hooked a air line to spark plug hole and air blasted out the breather hose, anyone know what I’m looking at now? I’d appreciate any help I get.thanks

The breather vents the CRANKCASE, not the top end. 
 
Air is apparently getting past the piston/rings into the crankcase.
Thus, "compression air" (that should stay in the combustion chamber)
is pushing engine oil out of the crankcase.  
 
 
If it's still running, I'd suspect a compression ring broke.
 
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