This has probably been posted before but the GM Heritage Site http://www.gmheritagecenter.com has posted Vehicle Information Kits in there archive section. These "Kits" contain an incredible amount of information on each specific model year. They list the 1902 to 1974 model years available for download. They include just about every Spec you could ever need. They also include body tag paint codes and interior codes with there corresponding aftermarket paint suppliers color number.