Before you do anything, first figure out exactly which Delco you have, what "Clocking" it has, and if the pulley and pulley spacers are special to that model bobcat.
You likely have an AC Delco 10SI. Since you're not driving a Cadillac or motorhome you likely only have a 37 Amp alternator. You don't need a high amperage alternator in a Bobcat. Sometimes they stamp the serial number and Amp rating right into the case. Looking at the vent holes on the back case half will help you identify which delco model you have.
The clocking is the relative position of the back half of the alternator to the front half. The options are 12 O'clock, 3, 6, or 9 O'clock.
The pulley that was on the Delco 10SI that was on our 443B was not the usual automobile type pulley. Make sure you keep the old alternator and pulley until you know for sure the new one will fit and the belt lines up straight with the other pulleys. They also make marine versions, one wire versions, positive ground versions of those alternators, but they are not common.
The Delco's were used on millions of GM vehicles, so if your backyard is hiding an old rusting chevy you might already have what you need. If you knew what year and model chevy to tell the local parts store you might be able to get the equivalent alternator there.
You could also rebuild it your self, they sell kits with new bearings, regulators, diodes, usually they are under $20, but if you've never had one apart it will take you few hours to figure out what goes where. It's usually not worth spending that amount of time to save 40 or 50 dollars.
Post up a picture of the alternator if you can. I've found this link to be informative.
http://www.madelectrical.com/electricaltech/delcoremy.shtml
