Oil recommendation for my 1970 dodge dart with 318 engine

We changed the oils at 1000 miles because the oils were not as good as they are today. Sludge was a big problem if you delayed the oil change.

Many people still used non-detergent oils thinking a detergent oil would make the engine have bubbles coming out of the breathers and road draft tubes.

I remember when the dealer I worked at (Mopar around 1969) recommended a 1500 mile oil change... our shop techs laughed at that predicting many worn out engines!