['68OrangeSunshine]

I would go with Valvoline Racing, since it has the ZDDP. Or use STP 4 Cylinder Oil Booster [w/ high ZDDP] with other oils. I like 20W-50 weight for a hotter climate -- I live in Tucson. Or straight SAE 30. [My 292 L6 likes that stuff.]
There are also some other ZDDP additives on the market that I haven't used myself.
If you can find new-in-the-box old oil marked series 'SL' or earlier, that's OK. Series 'SM' or later needs more ZDDP for our vintage engines.
Frequent oil changes are also a lot less expensive in overhaul costs, over all. I got 250,000 miles out of a 292 by changing oil every 2000 miles.