Using the old, now hard to find, non-detergent oil would be a poor choice for your motor.
That oil was the oil of the 50's.
I'm not saying it would harm your motor, but with better oils now available, especially Syn oils, the better choice is to use them.
As far as viscosity goes, engines of old did not have the tight tolerances that motors have today, hence the need for lighter viscosity oils today.
My new Dodge calls for 5w-20, my old one used 5w-30. Use what is recommended, it will probably give the best result in performance and MPG.
I know someone is going to say their motor runs or sounds better on this or that, thats fine, run it then if that makes you feel better or it sounds better.
I've done that, back in the 60's I ran my chevy motor on 40w Kendall Racing Oil.
But until you run it 100 k miles and then tear it down and check inside the motor, is that sound or feeling real mean much.
It might, and then it might not.
I'm not a big fan of additives, but I do change my oil more frequently than is recommended. When I lived in town and only drove short trips I changed it every 1000 miles.
I feel the best oil for any motor is CLEAN oil.
Dan
