Norsky, great thread wish I would have had it when I replaced mine. Would have been a lot less cuts and grey hair. Thanks

Dave,

Looking from the engine bay there is good size screw on the lower right hand corner. That looks like it unscrew from the inside. I wondering if I should go any deeper with it? Something tells me do it now. I need to put my gas tank back in before I take this on. I hate have to many things apart. Starting in march the vette goes to the shop for the engine install so the heater core has to be done. 

OK I have four bolts out is there a 5 one? The box will not come out. The center dash vent is still there does this have to come out? There are a lot of cables on the driver side of this I dont really want to mess with that.

There seems to be a nut in between the AC box and back of the firewall> It looks like I have to take the AC box off to get to that one nut. Is that the case. The nut is the upper left one facing the box from inside the car. Is this a another Buba job?

Here is a update. In my car you can not take out the heater box without taking off the evaporator box in the engine bay. Is that normal for all AC 70 Vetts? So the heater core looks like it had a small leak which might explain why there was a cut off valve switch on the heater hose. I spent a good amount time cleaning up the heater box. I order a heater core from Napa and today I will order the Heater box gaskets. I did take enough pictures I hope I can put this back in.