Classic/Antique Car Repair: Heater core, heater core, general description

Question
Need to replace the heater core on a 1972 Monte carlo. Any advice on how to do this is appreciated.

Answer
Don't recall a 72 exactly, but as a general description, remove the hoses at the firewall, then remove as little under the dash as possible to get heater core out.

I don't remember if this has the split box in front of the firewall. If it does, then that is where  you remove it.

Sorry