I have owned Porsches

Yes, the older 911's had Oil Cooled flat 6 engines. My 911 SC had a large whales tail, within the tail (most people never saw it) was a large oil radiator. As the wind came over the roof line , it also went into the tail to cool the oil. 12 quarts is what my Porsche required. The engine really needs only 4 quarts for lubrication, the additional 8 were for cooling the engine under heavy stressful operation (driving like an idiot without being on a track). It was a highly modified Volkswagen engine, after all Mr. Ferdinand Porsche was the creator of Volkswagen.

Oil changes pending your style of driving back in the 80's were between 10,000 and 15,000 miles with Dinosaur oil. You had to drain the engine case and the side reservoir tank.

Next time you see a Classic Porsche, just take a look at the top of the tail. Great and fun little cars.