I am at 3000 miles and did my 3rd engine oil change. I experienced oil consumption around 0.5 L per 1000 miles consistently, which is expected on 20 weight oil during hard driving.
I sent out used engine oils for analysis.
1st oil - factory 0W-20 , 1000 miles, under 4k RPM break in method - The oil was straight garbage, the oil didn't meet 0W-20 univeral requirements and showed high wear levels.
2nd oil - Ravenol SFE 5W-20 , 600 miles, hard driving - The oil was in good condition but the sample showed higher wear level than the factory oil. (Probably due to the hard driving and break-in not completed just yet).
3rd oil - Ravenol SFE 5W-20, 1250 miles, hard driving - Awaiting used oil analysis results, will update later. However just from the visual POV, the oil looked clean.
4th oil - Motul 5W-30 - my latest oil change. I will monitor behaviour and send a sample for analysis probably next year as I won't drive much in the winter.
If you use this car as it was intended, I strongly recommend to run 5W-30 even in the winter, unless you live in the arctic circle or Siberia.
BTW I also did my Trans (MT) and Diff oil at 3k miles.
Trans oil was fine and the drain plug showed minimal debris. However depending on the oil used, the oil can affect the shift feel, so you might consider that to make your shifts smoother.
Diff oil was another story. The oil was pitch black and smelled nasty, the drain plug had large amount of debris. Definitely worth the change IMO.
Note that my 86 serves as a second fun car and majority of my miles are hard fun miles.