It won't kill your engine but I'd run a 10W30 if you are using dino oil. You can get away with a lighter oil if running synthetic… IMHO of course.
Living the dream behind the Cheddar Curtain
'88 F-350 Crew Cab, 460 Fuel Squeezer
'97 Ram 1500, '99 Jeep Grand Cherokee. '90 Buick Park Ave. '52 Pontiac Catalina.
Plus a couple old dirt race cars.