A billet flywheel because the OEM cast one may and has disintegrated under higher RPMs of modified engines.
The 8HP Predator modified ST824 suffers zero engine power issues. The engine hardly changes RPMs at all. But, there is a lot of belt slipping when large quantities of snow or wet/heavy stuff are tackled.
The stock Predator is just fine until I come up with a way to significantly reduce the impeller belt slippage.
From my experience, the Predator engine is far smoother, quieter, and just sounds so much more well put-together. In a little more than nine days I've put 7.9 hours of actual snow blowing on the machine. I'm very satisfied.
As mentioned above, the belt is the current limiting factor in getting all that engine power into thrown snow.
Are you completely sure your belts didn't get wet?
Are those belts raw edge? From what I read last week raw edge belts grab better and can transfer more power. The original belts were raw.