Good article but he is wrong about the rear end option. Those barracudas came factory with the 7-1/4” or optional in 66 was an 8-3/4 rear. I believe it was the towing package. I know this because my 66 barracuda has one.
My 66 Dart has a 8 3/4 SG with no "towing package". Like always, Tony doesn't do his homework and goes off half cocked, spouting stuff that isn't true.