In my 54 car and my old 235 I ran straight 30 Rotella. The motor was old and tired, so I'm sure it was just happy to have any oil. I used rotella based on recommendation because of the slightly higher zinc levels. It could all be b.s. for all I know. I just replaced that motor with a rebuilt 235 that I got from Tom Langdon. He recommended using any regular 5w-30 or 10w-30 motor oil. I opted to go with Brad Penn 10w-30 motor oil. Is it necessary, I don't know, but the price isn't much different so I figure it's also not going to hurt. Just my 2 cents. To each their own, but I would stay away from the synthetic.
