Duane is right, somehow oil is getting into the combustion chamber. (white smoke is oil, black smoke is excess fuel) On an engine this old seals, rings, and clearances are probably starting to go away...........just old age.

Depends on what you want to do with the car. If you want to keep it stock, rebuild the old engine, but, as mentioned, these 300's weren't exactly the star of the Buick lineup, and had some little quirks. I had a '67 for my wife that had this engine, and it was always giving us one problem or another.

If you want to rod it, one of the later Buicks would be a nice swap, or a SBC using Chevelle mounts (I think)

For now, maybe a switch to a heavier grade oil, or an oil modifier, like STP would help somewhat?


Don