What kind of oil do I use

[TodFitch]

Cars from the late 1940s up probably always had detergent oil in them unless some owner when they were a used car was really cheap.

I use 20w-50 year round here. If I were to go up into the mountains in winter time, I'd switch to 10w-30 for that.

[RC Drown]

I use non-detergent 30 weight oil in my '40 also

[CHS]

30W oil is the way to go for temeratures above 32 degrees . In the old days, the oil did not have detergent in it. If your engine has never been overhauled, I would stick with non detergent. Using a detergent oil could dislodge sludge, and could clog oil flow.
If your engine was rebuilt I would use a detergent oil. I use Castrol 30W in my 55 Plymouth 6 cylinder.
If you live in a cold climate and drive your car in the winter you will need to change it to 20W oil. This is when the temperature is below 32 degrees.

[dmckay]

Another question from the newby.  Just got a 47 special deluxe a couple of weeks ago.  This all new to me.  Car has 86000 miles.  What weight oil do you all recommend.  Just a flat 30 or something else.  Also someone told me to only put non-detergent oil in her.  What is the consensus out there?  Thanks.