thats a cs144 with a v belt pulley^^
these aren't pictures of our alts, but just wanted to show some examples.
the cs144 is a little wider, but as long as your upper mount is adjustable(to set belt tension) you shouldn't have much problem. the mounting holes are about 1/4'' farther apart on the cs144
NovaResource - SI to CS Alternator Conversion
there's a little info on doing the swap.