Anything in the intake track will disperse the oil
over all the cyls... when you let off the pedal the
vac goes up and pulls the oil back into the intake
and will dump it in all the cyls and can make it look
like there is very little signs of oil.. I had a hole
in a intake runner and it pulled a qt of oil in 35 miles
and dumped it out both pipes... the muffs had a lot
of oil in them