5w30
I have Mobil 1 in the 292 right now.
I would love to use Rotella or Delo because they have (or did have) more zinc, but only if they had 5w30 or even 10w30.
20w50 is good for race engines that are built a little loose and torn down after a race.
Most engine wear occurs during engine warm up. 20w50 and STP would starve an engine for oil during warm-up and really srain the distributor gears. Modern engines have fast warm-up and run 5w20 and even 0w20. Fast warm-up helps with emissions as well.
I can't imagine how hard 20w50 and STP would be on an engine.
