I acquired an old LeMans with a worn out 326 once. I liked the car with the 4 speed but it smoked something awful. Back in 74 Mobile oil had started selling it's Mobile 1 syn. oil and claimed a higher flash point being synthetic. So, I decided to experiment with it and at 5.00 a qt. (really high dollar back then)
I changed the oil and WALLA! no smoke. Only problem was it still used the same amount of oil at 5 bucks a qt. and it smelled like crap.
The cop's can cite you in California for excessive smoke but not for wasting money and grossing out everyone that follows you down the road.