Hidden Heater Core Bolt?

[Vetteman61]

Hey guys,
Once again I'm trying to do things I have no idea what I'm doing. I've printed the heater core article from the site.
I have an '87 k5, so it has the ecm under the dash. I have all the bolts out of the heater core box, and what I believe to be all the bolts from the top, but the heater core box remains stuck at the top when I try to pull it out.
There were 2 speed nuts on the outside on the top and side. I even took a wire bracket lose from on top of the outside of the box. I took the one bolt free from the inside between the box and the kick panel. Is there another bolt somewhere on the inside, hidden that I cannot find? I can free the bottoms and the sides have a little play in them, but the top seems stuck firmly as though there's another bolt up there somewhere.
Hopefully someone has experienced this before. I'm gonna go grab a subway to give me some energy to deal with this frustration.

Brandon

 

[4X4HIGH]

On my 89 there is a bolt "hidden" under the hood between the fenderwell and the suitcase.

 

[sunnyc123abc]

I just pulled mine out today on my 84 k5. On the outside there was 1 screw, top left. Then there were 3 nuts, one top right, one bottom right and one on the bottom left, I had to use a long extension to get to that one. In the inside there was on screw on the right side. To pull it out, I had to tug on it a little bit because the top bolt was getting caught in its hole. Hope that helps