Classic/Antique Car Repair: no heat, pressure tester, dodge charger

Question
how do i replace a heater core in my 1974 dodge charger?

Answer
Jim;
Hi how / why do you think  \it is the heater core. I would first have it tested with a pressure tester on the cooling system, it might be a hose or cap or loose conection or heat cont. valee. I would do the heater core last. it is a pain. so take a pressure test to see if there is a sloew keak if there is you will get no heat.