My 46 year old Ariens is still going strong on the 2nd engine. It will go through anything! I just wish it were safer. Its got a single belt for the impeller and transmission. Its actuated by a lever half way up the handle. It does have a dead-man style clutch for the drive wheels unlike earlier models.
I inherited an old MTD which didn't throw the snow and always clogged until I installed rubber impeller paddles. The gap between the impeller and housing was so wide I could stick my fingers through it. Those paddles really work and can make a lousy snowblower work better!!!!
https://www.youtube.com/watch?v=HHCEacrKeJM
https://www.youtube.com/watch?v=-XLOCtrAYZc