The Ambassador; at least 1970 onwards, was a Rebel/Matador with a longer front clip and matching wheelbase. From the A pillar back; it was 'Matador' in dimensions within the same bodystyle.My grand mother had a 60 Ambassador Wagon [ "Cross Country" was what the wagons were called, JavelinAMX ], with the 327/270 HP engine and it would snap your head back when she hit the gas. Even left black rubber in the driveway and on the street.
Love these things. My parent's 72 Ambassador had the 304 which was smooth and economical. Shorter and lighter than the LTD and Impala of the period as well, but with similar interior room. Still a great concept.