i had a similar smoke issue. it turned out to be the intake manifold gasket on one side was allowing oil to get into the exhaust warming port of the intake manifold. tiny amounts of oil from the lifter chamber were going straight into the exhaust header on one side. it doesn't take alot of oil to make alot of smoke. the telltale sign for mine was drops of oil coming out of the collecter joint on one header when the engine was cooling down and parked on a hill. hope this helps. good luck.
