This is a picture of the back of the bracket. The bracket has a radius machined in that matches the distance from the top alternator mount to one of the 130/150 amp alternator "ears". The extruded boss, if you will, of the small adjusting arm rides this radius when tightening the bolt to tension the belts. The 2003-2007 Tundra had up to the 130 amp alternator; the 2003-2007 Sequoia had up to the 150 amp. I believe they were both for the towing package. Not sure. The Toyota part numbers for those alternators are 27060-0F040 for the 130 amp and 27060-0F050 for the 150 amp.
The second picture (left to right) shows a 130 amp, a 150 amp, and a 180 amp which is off of a 5.7. The one off the 5.7 bolts to the motor so is not adjusted. The adjustment is through a tension pulley on a serpentine poly vee belt.
Bill
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I really appreciate the detail you put into this post. That's very very helpful.