There should be cables and the floor vents.... but to take the interior box out, you must go to the engine bay. there is 2 nuts on top of the engine bay heater box and 3 on the bottom side. BUT, when Buick decided to install the interior box first, they put the inside box in first then someone from the engine bay put on two nuts on TWO of the studs therefore holding it to the firewall. It is usually the one on top closest to the heater hoses, and of course on the bottom nearest the hood hinge. So, you have to take the 5 nuts off first in the engine bay and pry the engine bay heater box away from the firewall. I put a screwdriver handle in between the box and firewall. it requires a 7/16 wrench and alot of scrapes on your arms to get the bottom one. Once you remove these nuts, the heater box drops on the inside and you do not have to remove the fender to remove the core. If you want to, you don't have to put those nuts back on to make life easier. also, 1-800-radiator sells those heater cores for $85
I have to get into a 64 heater core replacement someday- with a/c Complications expected, but what you had whatta pia
You can find the a/c heater core removal by looking on google... type in the words "1964 Buick Lesabre heater core replacement" there is a guy who posted pics and all for you! Awesome
I just replaced the heater core in my '72 GS. I believe the unit I removed was an original brass? copper?. It was easy to remove the heater box & the core from it. However, reinstalling the heater box was just awful. Let's put this way - several "expletive deleted" phrases were uttered at the time.
I found that the heater core you put in yours also fits my 64'.... but it's about 1.5" too short, but i made it work with hard rubber... boo yah
