Changing nova heater core 1970?

Anyone have any tips or steps on how to change the heater core on a non a/c 1970 bbc nova. Going to do it tommorow and have heard a lot of ways you can. any tips let me know|||never done a nova, but i am sure they are like any other Chevy, two hoses, a cable and about 10 screws holding it to the firewall. don;t have to drain the colling system, just undo your hoses and tie them up so they don%26#039;t; drain, drain as much coolant out of the core as you can, if you have it, use air to blow it out, then unbolt it, i don%26#039;t; know if it goes to the inside to come out, or if you can take it out through the engine compartment.