You machine has the star gear instead of a worm for the chute crank so it’s probably in the 10MLxx series of Ariens 10,000 series models.
There are a few possible belts.
- 34x104 which is 35 x 3/8
- 72047 which is 35 ½ x 3/8
Most belt places will let you return a belt if it does not fit.
You can tune it in by going to the Ariens site at:
http://apache.ariens.com/cgibin/ctrg0005?form=Download&model=10ml60d&serial=111&mantype=O&mantype=P&mantype=S&language=ENG&sessionid=28702A3AD72BF4C0AA733C4CB825206B&site=ARIENSS
Use 10ML60 as the model number and 123 for a serial number and you will get the 10,000 series parts manual which covers your machine.
Your machine is as good as a new model. The only real advantage of a new machine is they toss a few feet further and have the auger engagement lever which stays engaged when the drive handle is pressed freeing up your hand for chute control. You've updated your motor so your compression is probably pretty good and the machine tosses well.
Dawei