Every build is unique but the one thing I can tell you is to add everything up you can think of. Then triple it. Since this is not going to be a concourse type resto you are not going to have to research the exact gloss level and where and what color the paint stripe was on the steering box.

All that said it is still a 73 and not a 72. Parts for the 2nd gen "A" bodies are hit or miss. The best suggestion to building a 73-77 GM is to start with the best condition car you can afford. Just some thoughts from someone that has been there.

Of course in my case give me a 73 El Camino and I am going to put a 73 Grand Am front end and dash in it. Learn what parts interchange from all the series as there are many mix and match parts from all the BOP cars 73-77.