This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
Joe Coffey used two hose clamps, one at each end, and a better fitting hose
to fix an oil leak from the valve cover to the air breather on a
Shadow/Sundance. Dan LaBrake said the culprit was the hose that went from
the upper part of the valve to the underside of the air breather; oil
collects in the breather and leaks onto the engine.