Hey guys just did my heater core was not as bad as I thought it would be if anybody got any questions hit me up. Did it over the course of two days about 4 hours each day a lot of it was putting the dash back together I'm real perfectionist.

 

I'm sure I will be doing that soon on my '73 Vert. There's some strange fiberglass laid down in the wiper arm area where I'm afraid Bubba did some nefarious stuff.
So you had to pull the whole dash to do it?

 

are there any pictures? I'll end up doing the core in my 73 as well

 

First remove passenger Door sill, map pocket panel, kick panel, Center gauge console can be placed down. I left mine connected. Disconnect vacuum lines. 3 altogether. 2 in box one by kick panel. Remove hot cold cable on top of box. There are 4 bolts in box. 2 on top. 2 on bottom. Important!! 1 bolt is a stud it runs through firewall to upper left engine passenger compartment 7/16 nut. Once box is out remove small bolts 1/4 on box and 2 big brackets that hold core in place. Clean out box and inspect rubber on both doors. Change if bad . It's important.
That's how they make a tight seal. Check 2 diaphragms in box make sure they still work. Your new heater core probably won't be a exact match but it should fit. My core came with some insulation strips . Make sure you use them on outer part of box where it mounts to car. Also now is a good idea to change heater hoses. They must come off anyway . There are by passenger side right by starter and a bitch to get off I just cut them off. On reinstall of hoses don't kink them and try to route them like you found them. Also good time to check upper and lower hoses . Change if worn . Water pump, thermostat , radiator should be checked too. Add new coolant. You will loose a lot when u pull heater hoses off. Also I taped all vents and duct work . It made a big difference in air flow. Try to take lots of cell phone pictures. Makes it a lot easier on reinstall. Be careful with interior. Try to mark what screws go where. Have patience. Take a few Corona brakes all should be fine. Good luck

 

Was your car with or without factory A/C?

 

with factory ac. I have seen it done from engine compartment with no ac.