piston rings

Read the article on www.slantsix.org before removing the manifolds. Valve stem leaks cause oil to be sucked past when idling (high vacuum) a long time, like sitting at a stop light. When you drive away, you get a puff of black smoke. Leaking rings typically give a blue smoke under hard acceleration. Have someone drive behind you, preferably looking thru the exhaust into the sun as you step on the gas.