Heater Core Replacement

I have a 1981 vette. I need to replace the heater core. I have a 1981 chevy shop manual that I purchased to help my repairs on this car. I thought it would make it easer for me, but it seems to be more confusing at times. I followed the directions and removed the glovebox and the ductwork,but I am unable to remove the heater core assebly. It says to remove the heater case retaining nut (located under the hood ontop of the blower case). I have extensivly for that retaining nut and I do'nt see one.The heater case is loose to the left,but not on the right.I can't seem to get the case to slide out.I need alot of help with this project. Looking at a Chilton book it says the 1981 and the 1982 are the same. This is my first vette, and it seems I bit off more than I can chew!!!I am looking foreward for help with this problem and others I will eb asking,once I get this core replaced.

Im sure that someone with an 80 - 81 will jump in here to give you some information. I have done the 72 and 74 . Both of them had nuts on the engine compartment side that needed to be removed. They seem to always be covered with undercoating and are harder to locate. Take your time and dont let it frustrate you. You can do it!
Rodney

I got mine out but still havent got it in... but mine is a 75

I'm locking this thread down as the conversation is continued in this thread (click here).