I did not remove anything just added period correct service replacement pulley, bolt, spacer and lock nut.  I would suggest to use the new lock nut for street use.  The new nut looks almost identical.  I brushed the bolt to see hoe it would clean up.

For pontiac cars there are 2 different 80 amp setups this one for F body and another for A B C D E F G X

The difference between the two is where the belt is adjusted.  With this one (F-body) the belt is adjusted at the at the idler.  This was done to keep the larger 80 amp alt. lower to keep it from contacting the hood.  The second type for all other car bodies used the same style of adjustment of slotted brackets as smaller alt. due to larger cars have a taller engine compartment.  For both 80 amp setups the bracket at the front of alt. in the where the difference is, the large car is slotted, the F car bracket has just one hole. 

In either case the alt. and power steering pump brackets for the 80 amp setup are different than the 55 amp setup.  

On left of main photo are idler pulley and brackets and new and old pulley,  middle are 2 brackets for alternator front and rear and on right are front and rear power steering pump and alternator pivot brackets.

Included are all brackets needed to properly install 80 amp alternator in a firebird with a V8.  The 80 amp alternator was included when a combination of A/C and rear window defog or defroster was ordered.   I have included 1 pulley mounting bolt and 1 spacer and lock nut for behind where pulley bolts to adjustment bracket.  No other hardware (bolts washers and spacers) are included.  You should be able to get those from NAPA or the like.

Included are 2 idler pulleys in main photo 1 new and 1 old and what I believe is an original 

The old original swaged pulley matched one that was in a box in the trunk of my car when I purchased it in February of 1987.  The third photo is of the pulley that was on the car when purchased and is still on there today.   That pulley is machined with a 6203 bearing.  The new pulley included is a AC DELCO unit also machined and very close in appearance and uses the same 6203 bearing.  The swaged pulley is formed/rolled sheet metal and has a 3204 bearing  The bolt appears to have been installed when the bearing was installed.

3rd photo shows (not included) what I believe to be a service replacement pulley (off my car) next to the new pulley I have included.

I included the new pulley because the original pulley is not usable in its current condition.  That pulley will need to be restored by someone with a lathe because bearing has been swaged in place.  The rolled material will need to be cut with a lathe and then a new bearing can be installed.  

Last photo is of the low profile pulley bolt also off my car (not included) and a new bolt included.  These bolts like the one off my car are in photos on the internet and ebay if you order one it will look like the new bolts in photo not the low profile bolt.  You can choose (1)  silver or gold