69 charger heater core removal

[maidenoz]

Hello.  I am trying to remove my heater core on my car.  I removed the heater/ac box but am at a loss as to how to open the front to get to the core....  all screws and linkages are removed but front of box won't budge....   the shop manual mentions retaining clips but I do not see any and I'm assuming it means to hold the core in place inside, I can't even get in!  any input is appreciated.

[Honeywood hemi]

Hello
So it's a non ac box ? Or ac ? Have you removed the strap that connects the cowl to the front of the heater box stud ? Possible heater nipples are wedged on opening in the engine side firewall, did you remove all the nuts in the engine compartment including the one by the pass side of the car? Hope this may help

[Honeywood hemi]

If you have a ac box you will see 2 box drains they use a clip these are located down low in the engine compartment quite possible these are stuck too...

[maidenoz]

Ive got the box out but can't seem to open it....   its out of the car but I can't get that front compartment to open.  Its an ac box.

[maidenoz]

Is there a trick to getting the box open? Also, are the clips mentioned in the manual to open the box, or to hold core in place?  I've got to be missing something.....

[gtx6970]

I dont think there are any clips that hold an AC box together. At least I dont remember any
Should be 5/16" hex screws along the bottom edge and 2 hex nuts on each side
The upper edge has a formed over lips that interlock  to hold the top of the case halves together