Nice work as usual Steve! Where do you find the time?
Have you replaced the starter on the car yet? There is a known problem with the LS1 engines where the original starters are held in by one long bolt and one short bolt. The short bolt loosens or breaks and then that allows all the torque from the starter to stress the one long bolt which then breaks off part of the block. The best repair is preventative maintance which means replacing the original starter with the heavy duty truck starter which uses two long bolts. Here is one of many links you can read about it. I am going to do this with my 30th before it breaks.
http://www.ls1.com/forums/f6/broken-...-mount-171452/