are a good idea. Pulling the heads off with the motor out isn't a bad job. But I wouldn't recommend a complete rebuild until you determine it is necessary. I wish I could help you with the noise issue. Have you checked the a/c electric fan? That makes noise when it turns on, especially if your fan clutch isn't connected and cooling. Can you pinpoint the noise location?
Cheers, JBrobst
"A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing." George Bernard Shaw