if my memory is right the alt you are trying to install now is for a few years newer,
however I recall using a grinder and just taking 1/4" off
now all this info is being dug up from 15 years back in my head, good luck
Actually the Denso is the OEM alternator. The sleeve in the front bolt hole of the bottom bracket is there I'm sure to take up any space between the bottom of the alternator and the bracket. Trouble is it is a very tight fit and hard to move. I solved my problem with the technique I described in this thread
http://board.marlincrawler.com/index.php?topic=91531.0