What is a good oil for a new GM 350 crate engine? I always used pennzoil 10 40w in my 307. I live in CA for so it can get pretty hot in the summer, I need oil chosen accordingly. My younger brother uses 10 30w in his 350 but that seems a little too thin. I also need to know what oil has the proper amount of zinc so my cam doesn't go south on me. What would you guys recommend?