I bought a 1957 Thunderbird at an auction last weekend. Seems to be in good condition given the limited inspection I was able to do. Now that it's home there is one potential area of concern. I'm getting some grayish white exhaust smoke that wasn't present at the auction. Looks the same from both sides. There's a little wisp at idle, big puff when I step on the gas and seems to go away at a constant 1500 or so rpm. I don't have it titled yet so can't take it for a drive. I'm wondering if it wasn't present at the auction because it was warmed up? Oil looks good so I don't think it's antifreeze. Maybe worn valve guide seals?

A couple more general questions. What's a good modern oil to use? The manual calls for 20 or 20W. I'm guessing I need ZDDP in the oil or an additive.

What grade of gas should I use?

Thanks.