I checked out your Impala pictures just to make sure that we are talking 2-Door cars. If they were 4-Doors, especially if they were both Sedans, everything would be exactly the same as far as sheet metal goes, but with the Impala Sport Coupe vs the Biscayne, the Roof, Doors, Glass, and Trunk Lid size, will be different. Also the Rear Seat and Rear Side Panels will be different in size as well as being a different style. Also there is just about no Biscayne specific parts offered reproduced, but that would not stop me from fixing one. The 2-Door Biscayne is very much in demand car. Keeping it all original would be ideal, but it is a car that many people like to drop a Big Block, 4-Speed in. Will be looking forward to see some pictures of it.