[markjohnson]

This one's really gonna rock the boat, but back in the late eighties, we took a 1970 454 4-bolt engine out a 69 Camaro street machine that was DEFINITLY coded as a 450 HP, aluminum head LS6. I don't remember the exact engine suffix, but the code does exist. The alum heads had been replaced by a set of late 70's oval ports and the block had a cracked cylinder wall. I think the block ended up getting thrown away but may still be around.