Thanks Bobby. I have a 67 fastback S code owner claimed it was a 67 date coded cobra jet. Obviously not theat motor since it came out in 68. Now owner not sure if its a 390, 427 or something else. That's why he sent me the "C5AE-A" block code. I thought it was from a Galaxy from my resarch. Maybe a 427 but who knows and I can't afford flying around opening motors to really identify them unless car is a steal.