I would not recommend 20w50 in any healthy engine. For one with severe consumption issues or a rod knock it has it's advantages though. My cousin buys his oil at the local farm supply and puts 10w30 valvoline in everything. He has had no issues with his truck. If he is still around this site I believe Jim Allen was doing something very similar so he only had to buy one grade of oil. 5w20 may be recommended maybe even optimal but if you think that putting in 5w30 is going to do any damage you're drinking the kool-aid!