I'm considering putting it in a 1978 Caprice. I've had the car 22 years and it's still my daily driver. I recently did an LS swap and I've never really liked the dash design of those cars. Before I go much further I need to make sure it will physically fit between the a-pillars and doors. The B-body Caprice's downsized in '77, and they went down to the size of the Grand Prix's previous intermediate size from 73-77, so I think there's a good chance it could fit, but I can't find any other examples online.
This picture (not my car, just found online) is of the same type of dash/seat setup that I currently have.
And here is what I would like to install (photo of '73 Grand Am).