How do I delete my AC?

1974 Duster with factor AC. I pulled all the components on engine side of the firewall. Can I simply cap the old pressure lines at the fire wall and run my heater core as it was originally hooked up? Or, should I pull the AC box on the inside too? I just don't want that big POS AC unit on the car anymore. I guess I'm looking for the easiest way to retain heat and dump the AC. Thanks. I did search and I looked my factory manuals, but neither really gave the answer I need.