You've either got a bracket for an old V-8, like a 283, or the alternator isn't designed to work with that bracket. I'll bet one of the older external-regulated alternators has a different spacing, or you've got the wrong bracket. Either way, you're going to need to modify something. It's easy to make a bracket, though. I do it all the time on racing engines where no standard brackets are available for the setup I want.
Jerry
