I haven't seen this here so I thought it might be of interest. Unfortunately it only goes as far as 2006 or 07...can't remember. Has lots of good info including RPO codes and torque values....
Vehicle Information Kits - GM Heritage Center
Access free vehicle information kits (PDF downloads) for General Motors vehicles. The kits are part of the GM Heritage Center archive, including archived documents, artifacts and assorted automobilia from General Motors.
www.gmheritagecenter.com
