73 dart v8 removing heater and a/c

Refer to picture for what i am referring to. What is the best way to remove the heater core? and can these pipes(circled in pic) be removed somehow if so what is the best way? i will be covering these holes in the firewall with fiberglass after removing the internals.i removed the glove box insert today to see if i could just unbolt the core and remove but it did not appear to be that simple any help would be appreciated.