Please call your local chevy dealer.Ask the service dept who does there leather seat work.They will give you the phone number of a local shop who does the best work that they use.Hope this helps.Best of luck.
Check your local junkyards. Some of the full-sized buicks and oldsmobiles are a direct swap into the b-bodies with little to no modification needed at all for install. I got plush civilian seats and put them in my '90 9c1 when I owned it...What an awesome difference!
there is a cool place out here in cali called Henry's Upholstery.....they are super cheap and do great work, especially if you take the seats out of the car and take them to him. if you want to save more cash, remove the seat skins and take them to him to match and then install them back yourself. i took a leather front bucket seat to him to match. it had 3 colors, piping, and some different textures stuff going on, plus a headrest. he did the removal and reinstall. it looked factory when it was done. it cost less than $150 including tax. i thought that was a great deal but maybe i am wrong?
oh...he also replaced the foam that was smashed to bring the seat back to its original shape.
Any B-body seats will directly fit into another b-body seat wise. You might have an issue if you are trying to swap a split bench into a car with a strict bench seat, because they don't have the inner seat mounts. It wouldn't be too hard to weld some in though. Cheapest route would be to find a set of used in the junkyard. I just sold a set of mint cloth seats for $80 from a 1994Buick Roadmaster, and they did fit in my 77 Impala.