Welcome to the Team Tom!
You should be able to use the seats out of a 1965-'70 Impala, Caprice, Bel Air, Estate Wagon from any two door car. The four door rear and front seats are different and will not fit right. You are going to want to match your fabric to what ever trim level you have on your car (different models offered different fabrics and patterns.
That said; if you are going to recover the seats with new fabric then you can grab a set of seats out of not only the Chevrolet cars I mentioned but look at Pontiac, Olds, Buick, and Cadillac cars for a similar or upgraded your seat to a higher quality interior (with power seats, or split bench with dual arm rests, or reclining five way power bucket seats out of a Caddy). The diferent marquees all have the same front floor pan and rear seat floor pan area (though the Caddy has 11 more inches of leg room)so they will all bolt in (this assumes you are looking at B-body cars from your year to 1970).