Nion, you have mail.
Nope, it is much smaller than that. Mine came from a '77 Camaro motor and it holds the alternator like it was made for it (almost). Look at the pics I sent you--they show it installed and all, but you won't really see too much of the black bracket on the black motor, behind the alternator. Frankly, I would not pay much at all for such a bracket--they are practically free at the junkyard, etc. $19!?!?? for that ebay bracket? Sheesh, no way. I hope the pic does help some--if you really want to pursue this, I'll pull the alternator and invite Auxilary to come over and snap a pic or two. Just let me know.
Davy