Re: oil ?
Any of today's oils are mfg'd to a higher standard than what was produced in 1991-1993. Lack of zinc in today's oils is supposedly a problem for a flat tappet cam. Some say you need an additive such as ZDDP (available from a board member here) and others say the general upgrade in the oil itself is sufficient to overcome any definiency due to the lack of zinc. At this time, I have no proof of either on the flat tappet cam other than adding the zinc additive doesn't hurt.
Mineral based vs synthetic or a blend. Again, any of todays spec oils should be sufficient. Synthetic flows faster and easier than any mineral based. One thing that is not widely discussed is about one of the multi viscoty weights. As shown in a photo above, there is a 0w-30. When an engine is cold, one of the objects is to get the oil through the entire engine as quickly as possible. A 0 weight will do that quicker than a 5, or 10w ect... As operating temp increases, they all become a 30 weight. So why not go for the quicker flowing at cold temp oil? 0w30 synthetic will do it quicker than others.
Then there is the theory/fact that a synthetic will last longer (not break down) as quickly as a mineral based oil so you don't have to change the oil as much. 2 things on this one (imo). They both get dirty equally based on mileage. I change my oil more frequently than any suggested oil change interval so I don't need the super oil that claims it can go 10K miles between changes. Glad to know it can do it, but, I never let it go that long.
I like Castrol Edge (new name for their synthetic) 0w30 European spec formula. Have 246K on my DD with it and no issues. Although some oils are proven to be better than others in certain situations, I assume that all of todays oils are sufficient for a great majority of applications.