The crankcase bolt turned out to be a real challenge, it is in fact still securely in place. The impact wrench I had available did not move it. When I borrowed a breaker bar from the neighbour it only made the engine turn CCW, not a good thing.
Hopefully I can come up with a way to block the engine more effectively tomorrow or find a more powerful impact wrench.
Owning and driving a Porsche 911 SC 
Wow your bolt is on tight! Mine came loose just with the car in gear and a modest socket wrench. Tom actually put one of those on my shaft when we did a transmission swap and other bits on the engine. Mine was not leaking (in that location) but why not put one on any way! 🙂 I enjoy your blog.
I’m glad you enjoy the blog. Yes, it was a struggle but now it’s finally off, phew. I never thought of installing one as a precaution but it sound like a good idea (if you’re in there at least :).