There is other factors not even mentioned by oilman though, as in real time tests.
Remember mobils old oil add a beemer driven non stop showed so, little wear after many thousands of miles, odd as most wear occurs when cold, which it never was of course.
A certain us university conducted oil tests long term over 400,000 miles on some engines, truck/hgv taxi's and anything in between, interesting reading, some "performance" oils were slated as they did not hold their viscosity mobil 1 was one such oil as was castrol rs from memory.
A major problem with the cossie is imo the low quantity of oil so it has a lot of work to do, heat transfer was not even mentioned, oil transfers at least as much heat as water cooling does, uni tests found on average engine oil was 30C hotter than the water/coolant temp.
I used 60 weight oil in mine as it was so knackered, but also often 20W50 GRANVILLE oil, a MINERAL oil at that without any problems or undue wear, despite ragging the tits of it, but then by virtue of it's thirst for oil it was always new, so no problem.
I would use a good fully synthetic oil of a 50 weight in most, apart from running in of course then mineral 40 weight for me, for first 2K.
I'll be using SUNOCO RACING 20W50 as the oil also has a good detergent package, very important for road cars, as is getting the oil nice and hot every now and again to burn off dilutants/moisture in the oil.
I used to change my oil around every 12,000 and managed 200K on the engine before tear down.
I've gone for a bog standard chinese made oil pump for a pinto with a std 60 psi/ish pressure, the people I use use the same pumps on all their own supplied/built race pintos but each one is individually checked and as much as 50% of the pumps are rejected, due to not being good enough.
tabetha