Daytona Heater Core

I am in the process of refurbishing the cooling system (hoses, water pump rebuild, radiator pressure test etc.) on my 1973 Daytona and would also like to have the heater cores tested as well. It appears that on the left side heater core housing there is a small bracket which the washer pump affixes to. The bracket looks to be tack welded to both the core housing and the metal shroud on the firewall to which the brake booster's cast frame is attached. I have located both the upper and lower bolts that secure the heater core housing in place but I'm not sure how the housing is removed given the above noted bracket. Wondering if anyone has removed their heater core and can offer any advice? The right side core housing removal seems fairly straight forward. Any suggestions would be much appreciated.