What engine oil do you prefer,??.

Lots of people used single weight "tractor oil" long before the inundation of synthetic oil for automobiles and got a LOT of mileage too. The key to it is keeping it changed, plain and simple. Even the best synthetic can and will fail if it's not changed properly.

My point is, ad you seem to have missed it, is that the OIL, while important, is NOT the end all be all. Proper maintenance is.

You can throw up whatever article you want, that doesn't make it the end all be all. Evidence shows otherwise. My grandfather had a 65 Rambler American 2 door 6 cylinder 3 on the tree and always ran straight 30 weight. It had over 250K when he sold it. He's but one example of millions. As I've said before, for the most part, all the engine cares about is whether the dipstick says full.