I have converted these cars from manual windows to power windows and it is not for the faint of heart. I would only recommend it if a person is doing a restoration or major overhaul of the car (it is that big of a job).
With that said, I have converted quite a few manual window doors to power (and vice versa) from accident damage and that is a much easier job (still not easy) than converting the entire car. A person needs to get remove the window regulator – which requires a 1/4” drill bit/drill, a small punch (1/8” - I think) and a 2-3 pound hammer (no wimpy nail hammers). Once door panel is off – remove the door glass (if possible) to prevent damage to glass. Take the punch and punch out the three window regulator rivet pins (which are steel, inside of an aluminum rivet base). The pins should fall to bottom of door, never to be seen or heard of again.
Take the drill with 1/4” drill bit and drill out the rivets (a pretty quick job). Using either two or three hands (you do have three hands??) remove the window regulator from the large hole on lower (inside) door hole.
I recommend removing the window regulator if you need to replace/repair the window motor - than trying trying to replace the window motor with regulator still attached to the door (almost impossible to do inside of the door).
When going back together and if you don't have access to a monster pop-rivet gun (normal size pop-rivet guns can't do 1/4” rivets, even if they fit the gun) then go to hardware store and get some 1/4” bolts (1/2”, 5/8” or 3/4” long will work) and nuts and use them to reattach the regulator. If you do have access to a monster pop-rivet gun (with 18” arms or hopefully 24” arms) then go for it. Even a gun with 24” arms it still takes a lot to get those suckers to “pop”. Pop rivets can make the job faster, but if you don't have access to one, there's nothing wrong with nuts/bolts.
In theory, all 4-door F & M body ('76-89) window regulators should all interchange – with the exception the parts for each of the four doors are different from each other. Now that I said that, I might be proved wrong.
The '70's cars will have a higher frequency of having manual windows, as well as (all year) police cars.
BudW