It could be either way. Without A/C, a '65 or '66 radiator will interchange. The core support is made for a 22" radiator. When they used a 19" radiator, one of the radiator brackets is wider to take up the space in the opening. With A/C or heavy duty cooling, they came with a 22" radiator. Either the 19" or 22" will fit and work for your application. '64 models were all 19" radiators, but, they only had a 19" core support to match, so they won't bolt into a '65-6 without modifications. They also made both 2 and 3 row cores too depending on how much cooling capacity was required/desired.
