This conversation has been had on this site before and I think the uncertainty of the oils used is because everybody has had different experiences with motor oil over the years and as oil formulations have evolved chemically, more questions are asked as to there compatability to older motors which all started life out with petrolium oils. I have an original freshened up standard bore 396 which I use pennsoil 10w40 and add lucas oil additive for the cold starts. I drive maybe 200-300 miles a year and change oil yearly. I use Moble 1 in all my vehicles for the last 10 years or so and don't know if the miles driven warrent the expense. I would entertain BP or Rotella if they were proven better than the modern oils.
