Have the shop cc the heads. That's all you need to do. ....unless you're suddenly going to try to go for quench <rolls eyes> then you need to measure the depth of the flat part of the chambers....plus, they all need to be VERY close to the same AND all of any sharp edges need to be polished away. Nothing for any hot spots to develop and cause detonation. As I said. It's a lot of work.
