I'm a big believer in high-ZDDP oils in an older flat tappet engine. That's the stuff that oils of the day had in them.

I'm running Valvoline VR1 in my 289; I find it at my local O'Reilly's or NAPA stores. Brad Penn makes a good one, and I've seen that Hemmings is marketing a synthetic blend with ZDDP also.