Easiest 727/904 rebuild thread...
No hypothetically continuing this thread and I will do another one when I do this with good parts but let's call that one hour taking it apart and then I would say about an hour on each one of the three to four subsections so maybe four more hours getting it all correct for the subsections and then another two or three hours maybe to put it together you can imagine just doing this in one hour section should probably have 8 hours into it. That wouldn't include like scrubbing and cleaning and maybe painting the outer casing and stuff like that if you want to get real fancy and I usually do.
This is why I pro should be doing about three of these a day...