B engine alternator bracket........

In need of an alternator bracket for my 383 and came across one that only has one bolt hole for the alternator pivot. It's stated as fitting the low deck but the ones I always see (stamped steel anyway) have two bolt holes, for both B and RB. Des anybody know or have a bracket that they could measure to get the bolt hole distances? 4 3/4", 5 3/8", 5 1/2" are the bolt hole centers on the one I'm looking at. I appreciate any help and thank you in advance.