Introducing the O.S. 21XZ-B and the Speed Tuned 21XZ-B, the hottest engines to hit the 1/8 scale scene in years! Both deliver the championship-caliber performance you need for first-place wins, providing improved torque and acceleration on demand. The 21XZ-B represents how far engines have evolved since the 21VZ-B V-Spec, the most successful racing engine in O.S. history. The 21XZ-B delivers more power than its predecessor, while using less fuel. A lower center-of-gravity improves handling, and a 21J2 carb with 7 mm restrictor adds further fine-tuning. Also available, the Speed Tuned 21XZ-B takes power to even greater extremes! Refinements, like a black-anodized cylinder head and a DLC-coated crankshaft, improve cooling, reduce weight and enhance fuel flow. As you watch this exciting video featuring the two engines, you'll quickly discover that, no matter which 21XZ-B you choose, you can expect exceptional O.S. quality and performance... and nothing less! OSMG2050 – 21XZ ABC Displacement: 0.21 cu in (3.5 cc) Output: 2.5 hp @ 33,000 rpm RPM Range: 4,000-40,000 Weight: 12.6 oz (357 g) OSMG2051 – Speed Tuned 21XZ-B ABC Displacement: 0.21 cu in (3.5 cc) Output: 2.6 hp @ 34,000 rpm RPM Range: 4,000-40,000 Weight: 12.5 oz (355 g) Both require: Glow plug, muffler, tuned pipe & manifold. Learn more about O.S. 21XZ-Bs by visiting their product pages at: http://www.osengines.com/engines/osmg2050.html and http://www.osengines.com/engines/osmg2051.html Join O.S. on Facebook at: http://www.facebook.com/osengines