Here is a Blackstone oil report from my '95. This is from oil that was from a relatively fresh engine rebuild, hours approx 2-7. Previous to this I sent in a sample of the initial break-in oil. The results of that analysis were frightening. Very high levels of metals and other compounds. It caused genuine concern but after speaking to engine builder and another experienced SM engine builder, both told me the same thing. Don't be concerned with how break in oil looks. Break in oil itself has a lot of extra "stuff" in it and the oil picks up all the assembly lube and other break in chemicals and initial rebuild/break-in seating wear.
At that point I changed the oil, did some dyno and track time and sent in a sample of the 2nd oil from the engine. Huge improvement in the numbers which is an indication that it's healthy and that the previous advice was spot on. Will probably sample oil change #3 but really don't intend to do this too often. The test is cheap about $30.
Here's the report for anyone that hasn't seen one before. Oil is Mobil 1 Racing.