I think the 66 is separate also. The heater box is directly under the glovebox whereas the a/c is in the center.
Drain the radiator, pull the heater hoses, then pull the glovebox and disconnect the cables (take pics) and electric plug. Then pull the fresh air vent. Can't remember from there lol. Seems like there's a stud between the heater hoses on the firewall and a nut under the dash near the heater hoses that needs to come off. Maybe two other nuts on the firewall that need to come off. I only done it the one time this past June(?)
Oh, and I paid like $52 bucks for a new core and had to bend the inlet and outlet tubes slightly to get them to fit. I should have rebuilt the original.
