Originally posted by mcdanida
I'm a little hesitant to imaguine it's a 361 Henway, but it could be???
You just made the geezer's day, he's loves to hook 'em!

If you're sure of the number, then it's probably a crate engine replacement block. Follow Street's advice and call GM directly, it's obvious several here have done a web search for you and that number doesn't turn up.