[M.D. Holloway]

Pinto - rings in my ear like Hazle calling the cat. Commissioning is important and I would tend to want to stick to one oil. Reason being is that if there ever is a problem, tracing root cause becomes problematic when more variables are added to the mix. The oils are miscible and can be mixed but the 20W30 oil may be too light. If that is an 80's flat 6 then the 20W50 is really the weight you want to go with according to anything I have ever heard, read, seen, smelled and slipped on.

You don't buy Orange juice on price, you don't buy ground beef on price and you sure as heck better not buy house paint on price. So why would you even think that price should be a consideration when selecting an oil which as we all know has a direct influence on engine reliability and performance?