Warning, don't read this unless you're really bored or want to be!
Snow shoveling always hurt my back. When a friend moved down to NJ one year he sold me a bunch of his crap and it included a little 4 hp tracked craftsman snowblower and a radial arm saw. The radial never worked other than as a whole house light dimmer and has sucked space in my small garage for 12 years. The snowblower actually became a delight. It had to throw the snow on the right side 3 times to get it off the left side into the yard. My freaky neighbours don't want snow on their yard because it'll kill the flowers. Anyway, it did a great job of getting every last bit of snow, was really easy to turn yet went dead nuts straight near cars and was geared like a tunnel boring machine. The choke was goofy and overly sensitive and had to be played with. I couldn't fix it, took it to a shop. To my dismay my baby was just outdoors with a 100 others.
Decided to treat myself and bought an Ariens with a real differential, added tubes to the tubeless. It can really blast snow all over. It's lowest gear was about 3rd on the Craftsman and the Craftsman top gear was maybe as high as 3rd on the new one. Anyway, it's a bugger to control and a pain in the back because I usually shovel both my place and the amazingly perfect neighbours on the other side (generous and caring but never nosy) and by the time I'm done my back hurts. Having the diff lock up on the panel rather than in front of the muffler is probably effective in not using it as much unless it's big dump of snow and its gonna save a heart attack. Having it up top would make it turn easier and go straighter on the straights.
So as an experiment, I shoveled tonight instead of sparking up my orange carbon emitting snowspitter. No emissions controls here, heck no intake controls as far as air filters on these very ungreen items. It took me the same amount of time to shovel my single drive as snowblowing our 2 fairly generous 4 car (2 x 2) driveways.
So I'm 4¼ HP equiv as a thrower of snow yet can't sustain ½ HP for very long at all on a bicycle using bigger more efficient muscles. That's why I say equiv, at least for the first 20 minutes. Then again, in equivs I can go between ½ and ¼ as fast as a car over a very wide variety of hours.
Kudos to the newer designed shovels. Great for tall people that are too stupid to move south...