Yea, SD-455 for 73 and 74 only. But, this one is a PROMO. $120k!

http://images.google.com/imgres?imgurl=http://www.corbettsauto.com/pictures/1976_SD_Trans-Am/1976_SD_Trans-AM_John_Schinella.JPG&imgrefurl=http://www.corbettsauto.com/1973_sd_trans_am.htm&h=749&w=1341&sz=322&tbnid=27VVUYXKCbkJ:&tbnh=83&tbnw=150&hl=en&start=6&prev=/images%3Fq%3Dsd%2B455%26svnum%3D10%26hl%3Den%26lr% 3D

Sweet!