Here's how I changed my 44 tooth spur to a 49 tooth spur. It'll give you about 11% more low end. My top end stayed the exact same (38 mph) b/c with the 44 t spur I wasn't able to pull max rpms. Changing to a lower tooth clutch should work, but I was worried I wouldn't be able to adjust the engine far enough in to get the gears to mesh. I also have a 52 tooth that I was going to try, but the 49 barely clears, so that's about as much as you can go.


Here's the spur I used. http://www3.towerhobbies.com/cgi-bin...&I=LXFKM1&P=ML. You also need a 11x5x4 bushing and a couple washers as shims to make this work. I just bolted and glued one of the gears from the regular gearbox to this gear to connect it to the drivepin on the shaft.