You can find great repair manuals with step-by-step instructions, diagrams, parts locations and other important information here: http://bit.ly/mitchell_repair_manuals_online
Or here: http://bit.ly/AllData_Repair_Manuals_Online
drain coolant,disconnect the 2 hoses to core on engine side of firewall,inside you will have to unscrew majority of the passenger side of dash and prop out with a piece of wood etc. to access core and open up heater box.remove screws to core. remember how you get core out of box and re-assemble.you will have to play with all those lines etc. that get in your way,etc. good to have a 2nd person to help guide from opposite side of firewall. took me 4 hours in a freezing garage. good luck!!