Everyone else has covered this well, the one thing I can add is that the valve springs won't last forever. Change then every 3-4 races depending on how high you rev. If you are regularly going over 7000, like running a 4.11 at Rd Atl, change them every weekend. This will save you a lot of trouble down the road.

As you get ready to build back, if you are building yourself, I have a torque plate for the Z engine. I am in Shelby NC. I was amazed the first time I measured a block that had been done with a torque plate. The difference is huge.

Mike