On the 1960  and up models,  the power seat did not use recessed floor panels as on the earlier models, rather the seat frame itself was shorter in height, as Wizard says, on the power seat models.  I found this out exactly like Wizard did,  when I first installed a power seat track on my former 1960 Dodge Polara.  It worked fine, and, unlike Sven I was able to mount the switch with No Problem into the aluminum side frame of the seat.   However the seat sat much too high when it was in the top most position.     I always kept it in the low, rearward tilt position which was fine for myself. 

Now, if you happen to have a 1960-61 model with swivel seats, or the 1962 Chrysler 300 with the  three-section front seats,  the manual and power seat uses the same frame as the power seat,  but the manual seat has extra U-shaped brackets spot welded on the rear mounting points  to keep it in the higher position.     These brackets can easily be removed to allow the seat to sit at the correct height.   When I owned my former 1962 Chrysler 300,  I ground off the welded brackets when I installed the power seat frame onto my own seats,  so it sat at the correct height.    It was a very simple job on that car.  My current 1960 Chrysler Saratoga already had the Power Swivel seat option from factory, so I didn't have to do the conversion !