I have a 76 450 sel and am doing the rear seat and back at this time. On mine the rear seat has 2 cut outs on the front lower sheet metal part of the seat. This is where the seat is secured on to a couple of projections from the car body. Seat removes by lifting front part "up". The seat cover has a 3/16 '' by perhaps 3/4'' strip of cardboard that is sewed to the bottom perimeterr of the cover. This cardboard strip inserts into a slot built into the sheemetal seat frame at the bottom perimeter. Might take a little prying but the strip comes out and goes back fairly easily. A nice design I thought. I used the junk yard to get my replacement material. Good luck. Milt.

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Milterino
76 450 S.E.L.