You can remove the valves from the head and hand lap them. Its only a process to check that the valves make contact with the seats all the way around. Will give you a good guide as to the heads serivcability. While your doing it you can put in the new valve stem seals as well.
The more you do yourself the more you dont have to pay someone else to do. There was a time where it was everyones first head gasket job.
Either the book above or better still a dedicated factory shop manual for your model Luv off ebay.
The Haynes book is probably better to start you off, its a bit more in sequence for a specifit process and its a more simplified approach. Or best of both world get one of each book.
Cheers, Bob.
_________________
Current project, 1979 KB Isuzu Ute.
Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.