[V8 Bob]

I've used Valvoline VR-1 for over 40 years both as a break-in and regular use oil in HP ohv and flathead engines. VR-1 Racing street non-synthetic is reasonably priced and found in most auto parts stores, available in several weights; 10W30/20W50 and straight 30/40/50/60. My normal choice is 10W30.
IMO, you want to use the lightest weight oil providing good oil pressure. Unnecessary heavy oil can do more harm than good.