I don't remember removing the hinge, but it is so easy that I probably didn't think twice about it. I have had the hinge off numerous times to do various things, so I have 2 pieces of board cut just the right size to prop the hood up. I do remember the most time-consuming part of the job by far was removing the inner fender, because I had a bunch of rusted through U-nuts that would just spin when I try to loosen the bolts. One you've had the inner fender off once and have replaced bad U-nuts, it is easy to take off and put back on all you want.
If you haven't had the A/C box off yet for the first time in 50 years, don't be discouraged if you find work to do with the box before you put it back on. It's all quite do-able. Here is my journey and there's info packed in here:
https://www.67-72chevytrucks.com/vbo...d.php?t=790246
I have in my old notes the heater core box in the cab and the A/C evaporator box under the hood share 4 bolts that sandwich them together, and the heater core box additionally has 2 screws to secure it to the cab and a couple screws to secure the diverter box.