[Dave at Pelican Parts]

Another possibility is the hose going to the head vent. (If equipped; I've known some 72s with and some without.) This hose often gets exposed to a fair bit of oil and heat, so it tends to get brittle and crack and leak. Pull the hose off of the vent and see if it's still pliable. If not, cut off enough hose until you get to some that is. If you can't do that, then replace the hose.

Usually oil slopping out of the vent only happens during "spirited" driving.

--DD