got the 12si 94 amp GM alt in my trackick today, no pics (none needed really), here are my comments.
the alt came with a pulley for a 5 groove belt, after install the stock 4 groove fit just fine on the pulley without shimming or using a 4 groove pulley. used the T T alt bracket. not as heavy as i would like but seems to be working just fine. make sure you keep the plug that comes with the alt to hook to the stock wires if you (i recomend) go with the 3 wire hookup. stock battery wire from old alt works for the new one.
had 2 problems. 1st the alt is so big that i had to remove the pipe in the lower radiator hose and cut the bracket off of it. was going to buy a longer rad. hose but this worked alowing the alt to just miss the hose on the back side.
2nd and worst. the adjuster bracket for the stock alt WILL NOT work. so i just made 2 little plates w/ holes drilled 1.5 inches apart and raised the right side of the arm. long enough to get it done and short enought not to let it move all over the place. seen better ideas, but it works and only took 10 min to make
had to buy a new belt, it is 33.5 inches long. prob could have used a 34, but it workes.
Alt. works great!
will try to add a pic to my site and repost her later this weekend or next week.