[Mrmerlin]

Stray that oil is too thin, try some 10W40, if your using castrol i would try Valvoline, I have had viscosity breakdown with the castrol stuff in a few different cars, the valvoline never did breakdown , I change oil every 3000 miles and the filter as well ,use a factory oil filter.
The 944 engine has a weak link this is the #2 rod bearing journal, seems that when spinning at hi RPM with hot thin oil the centifugal force is enough to overcome the oil pump pressure, and oil distribution is lost to that journal...So...... good oil, keep revs under 5000 grand continuous operation, and if you do lose oil pressure and the new oil didnt change anything replace the rod bearings ASAP.
I think it is Huntly racing that adds a few additional oil holes to the crank journals, this lets the centrifugal fotce push the oil out to the rod bearing surface , and viola no more oil starvation related failures.....Stan