It wasn't a scam. Manufacturers have always given max. HP ratings, just like auto makers. But mower engines have a 'speed limit' of about 3200 RPM for safety reasons. So, an engine that produces 6.5 HP at 3600 RPM will produce less at the mandated lower speed. Duh. As long as everyone uses the same rating method, a 7.0 HP rating would always mean a more powerful engine than a 6.0 HP rating. So after a bunch of whiney-cats sued them, they now have to give torque ratings (usable work) instead of HP ratings.
The 'cc' number is cubic centimeters of displacement, or the 'size' of the engine. All things being equal, a larger engine makes more power. Currently, mower engines have grown to about 190 to 195 cc as a result of the horsepower war brought about by the trend toward mulching and self-propelled mowers. I say 'mower' engines because mostly that's what blowers have, or similar. So, if you need a very powerful snow blower, go by the rating and displacement, although the two do not necessarily go hand in hand. Like in motorcycles and cars, the engine's power depends on many factors other than displacement. Displacement is useful when comparing engines of exactly the same type, such as 4-cycle, OHV mower/blower engines.

If the manufacturer publishes the torque figures, you can still calculate the horse power with the standard formula. If the manufacturer doesn't publish any power figures, it's a Chinese engine and should be avoided.

I would worry more about the reputation of the snow blower company and whether the design is appropriate for your location.

A reputable company will include design a blower with an appropriately sized motor that will move snow in the amounts it was designed for. An HP or Torque rating by itself will not tell you whether the machine will work effectively or not.

Have you decided whether a single or double stage machine is most appropriate for your area? Just make that selection and pick a good manufacturer.