Larry, I'm not a Mopar guy but they are all engine's. Alan's advice is sound. I said what I did because a 20-50 was a popular oil for the roundy guy's but those motor's spend some time getting warm & buy the time the race is hot & heavy, the oil is @ 20 centistokes. Not so much in our drag racing. (unless it's a street/strip car driven to the track) I spent some time reading here:
www.bobistheoilguy.com
Then I put a wide sweep oil pressure gage in my daily driver (95 escort w/195,000 miles) & started playing with grade's. I know my racecar has different needs, but it's interesting.