Just bought my first 911, an ‘83 SC like you, and have been wondering the exact same thing. The oil was freshly changed before I bought it so I have a little time to figure it out but it is something I’m curious about. Obviously mine has a non-original AC compressor and plumbing.
The previous owner is a guy I work with and he said it wasn’t a problem… but it looks really tight to me. What I’m guessing is that the oil filter basically just clears the threads before it runs into the AC plumbing and from there you can rotate it out. I did order one of those oil filter change catch tray doohickeys from our host just because it was $7 and it’s either that or I stuff a ton of paper towels down there to catch oil from the filter.
In any case I’m really curious how it works out for you because a similar fate awaits me.
