Sorry but that is wrong. Only available with big blocks.
Are you sure? You may be right. I just looked it up in one of my Chevy books and they just note it as an appearance option which usually means no engine requirement was necessary. The only think I could find on line was at the Corvette forum. They just say it was an option.
http://www.corvetteforum.com/articles/c2/1967-corvette-stingray-overview.php