I must say I'm pretty impressed with this engine. I finally got to race it this last weekend and even with the temperature dropping 15+ degrees during the racing and causing it to run lean, I still didn't have any trouble with it running bad or flaming out. I was actually still running the glowplug that came in it (Dynamite #5) up until right before the mains. I only put a new one in it just to be safe. The old one still looks good, so I will probably put it back in for practice. The engine isn't ballistic, but it makes pretty good power from bottom to top. I was running a three shoe clutch with 1.1mm springs, but I think it should pull 1.0mm springs no problem (I like a lot of snap). I think if anyone out there is looking for a good backup/club race engine, this thing is perfect I paired mine up with a Dynamite 053, and I couldn't be happier with an engine/pipe combo that is less than $175.