Smoking 318 need some ideas why?

What probably happened is a couple of the cylinders got rust below the oil ring. after firing the grit made some stick.

There is a product called restore. add that to the oil and take it for a long ride . When you return add a bottle of prolong.

We do it on old tractors that sit for awhile that smoke. On some it works and some it don't. Its worth a try. it may take a little while.

Make sure your not burning excess oil out of the mufflers that could have gotten in there over time That takes some time to clear up. Steve.