I took the old heater core out this morning because I am replacing it while I am this far along. Im glad I did because when I removed the heater box I found a huge old mouse nest blocking the heater door and covering the core itself. I was careful removing the clamps and the core because I thought maybe someone would want original clamps and or core. If anyone from this forum needs them let me know. I will give them to you if you cover the shipping. I have no use for either the core or clamps and I'm not going to try to sell them. the core didnt leak when I bought the car but it has a green coolant stain on it.
Rodney

I hate those meeses to pieces!!!

Yea, they chewed a hole in the the shifter boot that was probably about 3" round. I knew it was there because of the heat that would come up thru the shifter so I already have a new boot here. Now I know why the hole in the rear astro vent rubber was from. They do alot of damage! But they are gone now. This was the 3rd nest I found. I do think its the last one as I have been over the entire car now!
Rodney

You're just as well to change the heater core. If it wasn't already leaking it would as soon as you got the car done. Shame on you for destoying our little friends home!

I agree with Jaws on that. I did not change mine while the car was apart and as soon as the valve opened to allow heat this winter it flooded the interior ruining the new carpet. The disassembly just to get to it has been a royal pain.

Phil, Sorry to hear that . Doing a heater core is not a fun thing to do. Thats why I decided to do it while I was this far. Its a cheap $50 insurance policy. I had already thought about when it starts to leak and being that my carpet is going to be a light saddle it would definitely stain. The next worry is do I use the original oil gauge because if that would leak it will ruin the carpet also. I havent decided yet but if I use the original gauge I will probably use copper tubing instead of the plastic tubing.
Rodney 

I had an oil line leak in a 72 El Camino. It also had a saddle interior and ruined the carpet. I use electric gauges now for that reason.

I replaced my heater core last spring because I got a real good deal on a new one. When I got the old one out I found out just how lucky I was. It was in real bad shape and would have been leaking very soon. one of the tubes broke loose while I was taking it out. Age is the worst thing for these cars.

Especially since the heater cores are cheap for Vettes (one of the few things)!

Brian, your pics show that green stain going down the side and on the pipe. Mine was just starting to show some green stain as well. Glad I decided to replace it and it really doesnt take that much more time if you have the dash panels already out. Sometime this next year I plan on replacing the one in my 74 as well.
Rodney