Before you pull and replace it, have you checked why its not working. Mine was as simple as replacing the heater element that in the rear. Mine is also a 1976.
Of course, you might have other reasons for removing it and so my comment is redundant.To answer your question, that was my main motivation for repair rather than removal. It looks like a beast to remove.
A wise man once told me he wanted to stay fit enough to run a marathon on his hundredth birthday. Another said he wanted to be shot by a jealous husband on his, I'm with the latter. God bless you Richard.
Carpet Cleaning is what I do, it's not who I am.