1983 305 H Series Alternator Adapter Bracket

[Huey]

I presently have a 305 H series motor in my full size Chevy Blazer, which uses a small case alternator. I
am trying to adapt a large case alternator to it, and was wondering if
anyone new of a source for an adapter bracket. It looks as though I only
need to increase the alternator bolt spacing by about 5/8 of an inch. It was suggested by the alterantor manufacturer that I could "spread" the brackets, but
hate to try bending the stock bracket for fear of disturbing the pulley
alignment. Does anyone make an adapter bracket for such a use? Any ideas?
Thanks