84 and 85 use a standard 12SI alternator, you can put the larger CS130 alternators like the Impala SS one in with a bracket from a 3.8 or 4.1 powered car that had the HD electrical system, like maybe a loaded LeSabre that had a V6 in it instead of the 307 V8 for some reason..
regarding the question asked by the OP: google the part number and see what comes up..