You were about to tackle a valve job so I would say you have the aptitude to read up on engine rebuilding and try your hand at that.
These books are a start to your journey and a VERY good reference to take you all the way through the process.
https://www.pelicanparts.com/catalog/accessories/rebuilding-porsche-911-engines.htm
https://www.amazon.com/Porsche-911-Performance-Handbook-1963-1998/dp/0760331804
At 177k miles you might as well take it all the way a part and keep the original motor running.
Good luck.