Re: Need advice on engine to buy
The chinese kits are considered a crapshoot. To avoid wrecking a new engine because of poor construction, don't slap the engine on right out of the kit and instead do a thorough teardown to inspect and do cleanup and porting.
The kit I got was from Raw Motors. This thing has dealt with so much abuse through experimenting, solder flux in the fuel, ethanol, etc, and it's still running awesome. It's a great engine.
Then there are Grubees, which a lot of people seem to be happy with, but I haven't had any experience with them. The one thing that would make me steer away from the Grubees would be the new CNS carburetor that comes with them. It seems like a lot of people have issues with them. I know that you can make it run well, but I shouldn't have to bust up epoxy glue just to be able to tune it(since the EPA makes them glue the controls shut). I know it's basic, but I love my NT carb.
Jet(brand name) engines are reported to be very good, but I don't know of any one place you can get them.