Alt. Replacement

What are you looking to do? If you're low charging or your alternator isn't putting out enough while at idle (ie lights dim, blinkers slow while at a stop light) then there are numerous threads in the electrical section with a ton of step by step instructions on how to find voltage drops.

The later stock "square back" alternators do put out more current at low idle than the earlier "round back" alternators. If you have a round back it could be part of your problem if you aren't getting enough juice at idle.