[OrrieG]

The heater core is inside of the metal box. Difference in standard and deluxe is basically the controls. Standard you get a knob to control the fan speed, but need to reach down and flip the feet/defront lever and temp control valve. Deluxe adds cable.lever control of defrost and temp. Unless you are going to be adjusting it a lot (I drove mine 20 years with broken controls so it was manual) or want the deluxe look standard is simpler. Some may have not been able to get a stock heater core and added the hole, or another, to make another type work. Lots of details on the system, including how to assemble and adjust in the FAM.