Way back when no one wanted firebirds, it seems that they were all clocked @ 12 o'clock, and all replacments--GM or aftermarket-alternators-were clocked @ 3 o'clock. The problem with clocking new parts is that they are often marked to show signs of fastener removal, voiding the warranry. That makes it a safe guess as to the reason why the 3 o'clock register--standared clocking on 2nd gen +--has now become "industry standard." I cannot tell, but it looks as if both alternators in the picture are clocked @ 3.

Unlike other people who don't mind coming off as most insluting, I add a disclaimer that I realise that some folks might not know what clocking means. I point out what clocking means because I realise that such configuration may not be common knowledge not because I'm an @$$hole and I view you as an idiot.

Clocking is the way the outer housings register. Remove the 4 long bolts that hold the housing together. Without taking the alternator apart rotate it one set of bolt holes. Based in the angle of the picture, it's hard to tell, but it looks if the back housing was rotated counterclockwise (looking from the back) one set of bolt holes, it would solve the problem.

Of course you have to make sure that there won't be a wiring interface problem.

Another factor that comes into play is that the mounting bosses on the alternator brackets can show signifigant wear. ALso,To judge how wear comes into play, eyeball the belt alignment. If it looks like whatever amount of spacing would offere better alternator alignment, the wear factor is also playing a role.