Brad,
Please get an out of the water survey.

You might also want to look at the spreader brackets where they attach to the mast. After years of hard use the brackets come away from the mast. There is a through bar kit from Annapolis Rigging that fixes the issue. http://j30.us/blog/?page_id=325.
I installed the Annapolis kit in the water, just some time with myself and a ladder tied to the mast.

The engine alternator is a Hitachi I believe. I'm still running my original one.

You might check the engine bed too. In the early boats they were inadequate. Here in Melbourne FL we have four J/30s, the oldest Sleighride was Rod Johnstone's original boat and it needed reinforcement of the engine bed. Mine is #406 and is OK there.

The J/30 is a good family boat but I am biased. Good luck with what you decide to do.