True, but that was the intended engine, that never went into production. And yes, they were offered over the counter.
http://www.ehow.com/list_7617778_gm-1970-ls7-454-specs.html
Several stories as to why they weren't produced, one being they had a problem with the aluminum heads, others because of insurance, and emissions. I remember reading an article in Hot Rod about both engines when I was a kid.