1965 Valiant 200 convertible (minor project)

Without pulling the engine or transmission, you can't tell. In '67 and earlier models, the slant 6 crankshaft and corresponding 904 torque converter used a small diameter mating hole. In '68 and later engines the hole in the end of the crankshaft was enlarged to the diameter all other Mopar engines used. If you mate a large diameter crank with a small diameter converter, you might not get the converter properly centered. That can cause balance/vibration problems resulting in broken flex plates and/or bushing/pump failures in the transmission. A conversion bushing is available for that situation, but, was it used or not? Many people don't know about it, or, the need for one.