I wouldnt, sounds like and appears its a good running motor that doesnt use oil, so continue using a quality oil, I myself use brad penn, , No Im not selling this brand , just hav been using it in my motors for long time, If u like do a search on this oil, and or other wise dont forget to ad some ZDDP to what ever brand u are using now.My sbc 350 is a mild build, probably around 300 give or take hp. Don't know without a dyno and other than tearing it completely apart for specifics I don't have any history or knowledge of what's in it. Heads are 1.94/1.50. Not pleased with that but it is what it is.
My question is would it be prudent to start running with motor oils made for high mileage engines? Casting # indicates a 77-79 Monte Carlo/Caprice engine, and I'm assuming it's got some miles on it. No, it doesn't burn an ounce (when running).