Wow, I hadn't heard that one before..... The pumps in my old Torino and also in the present Cougar had the very common "air growl" that would get loud now and then; but never that kind of rattle. Sounds like a bearing going waaaaaayyyy south and the impeller is beating the housing.
I've heard the A/C make that kind of noise; usually broken "clutch return springs" letting the clutch plates ease out and contact the inner surface of the pully. My Torino's compressor clutch started doing that about a year after I got her; and it did it 'til....... beats me, still did that when I let her go! The compressor clutch on my '72 F100 only did it for two weeks before failing completely; I took the belt off because it kept flying off and getting tangled in the fan. Took me a few weeks to replace the clutch - naturally, it's was in July.