Was "Gran Sport" ever offered in 1964 for the Riviera? I've never seen one before '65. Looks good though. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=6142&item=2429024063
No, the GS option only started in 65. Some 64's did come with the Super Wildcat engine with the dual four barrels and aluminum valve covers but that did not make them a GS. This is a fairly common misconception.