Heater Box Assembly for 1967-1968 Mustangs without air conditioning. The heater box assembly consists of the front and rear casings with doors. This is a factory type fiberglass two piece heater box/heater core casing. The heater box is a pre-assembled unit which includes the gasket and all seals. The heater plenum attaches to this assembly and directs warm air to the car.
Check out our video below on how to replace a heater core! We used a '69 Cougar with A/C, but many of the same concepts apply to other years.