It depends on the machine work as to how tight the engine is as far as bearings go. A 10 w 30 usually is good to heavy and you loose power and gas mileage.
I agree on the zinc unless you have a roller cam and electric fuel pump
T4 10w 40 Rotella it has Zink in it but still put a small bottle of Zink additive in also. New 383 just rebuilt. Solid lifter's and new cam. So this is what my engine builder say he tells all of his customer's to use even ford's and Chevy's. With flat tappet's. Have fun nice car.
my last 440 i ran 20/50 valvoline , it was in extreme heat to very cold , i beat the hell out of that engine for 10 years , never let me down, I'll admit it's a little heavy for freezing weather but it kept that engine in great condition, sold it to my friend and he beat it and was still running great when he sold it