Heater core in a 1973 dart
 

I bypassed my heatercore about three months ago cause it sprung a leak now that the weathers getting cold i am replacing it so i stared to atempt changing it and didnt make it far before i relissed i didnt know what i was doing so if anyone knows the easiest way to change it that would be much apreciated Thanks

Dont pull the entire box out, leave the controls attached. Take out all the screws, 4 hold the core in, 1 on top with a bracket, ect

Slide it out, slide the new one in slowly to make sure it fits. Pretty straight forward. Then put the cover back on and slide the whole thing back up.

Thank u very much for the input

You're welcome. Like i said, pretty straight forward. Just start taking things apart. you'll get to it.

Also, on the firewall, you need to take 4 7/16ths nuts off and the plate, as well as the screw and plate that slide over the heater core tubes.

THEN you can pull the box out...

I've done a few and the last one was on my blue dart.