www.bobistheoilguy.com
Mobil 1 15/50 supposedly has ZDDP added back into it to address camshaft issues. We run it in our Chump Car miata for racing.
Pennzoil Ultra is fairly new and claims to do a great job cleaning the engine. I run the 5/30 in the Expedition - not 20 weight.
Pick the right viscosity and keep it clean. This topic can lead to OCD.