Judd,
I added air conditioning to a '65 Chevy 283 4 door sedan once, and all I did was pull the entire system out of a salvage yard car, install it, and have it charged. If I remember correctly, the compressor bracket arrangement was pretty simple, and even with a different compressor, it shouldn't be too hard to modify the original or to fabricate one. I'd suggest a quick trip to the local salvage yard to take a look at an original factory setup, and I'd take the bracket that you just bought along to compare.