head gasket replacement.

I am having an issue getting a bolt out of the head of my kz650 b-1 (replacing the rubber carb. holders) and have spoken to someone who specializes in car head work. He also used to race a kz900 and did numerous head jobs on it. Is it a good idea to have him replace the head gasket when he takes the head off to machine the broken bolt out? Will this "split the block" - a KZ RIDERS NO-NO?... I am making another attempt to drill and ez-out the bolt this weekend. Thanks.

Soak the bolt with Kroil for a couple days before trying to remove it again. Ed