Re: Standard Horepower?
I had a Grubee GT5 (66CC) with a factory badge stuck on it with date of manufacture that claimed it was 2.75HP @ 5x00 RPM (forget the exact RPM it said).
Might have been about accurate with the stock kit gear it came with. That one had one of the black cat pipes. Seemed to have less power than 2 of the Dax 66 I had.
From my experience, the power varies widely with the bigger chinagirl engines. You might get a crappy one with lots of gear noise that struggles to rev, you might get an eager, quiet engine that runs easily and revs over 7K. Lots of in-between. There's 5 days in a week and only one of em is a Wednesday lol
2.5-3.5HP is about the range I'd guesstimate stock. There is no "standard" because build quality varies so much with them.
IMHO the important thing to consider with the 66 is the torque. They can make great torque without revving high.