This is the TRA TRX 3.3 Racing Engine without Starter and with IPS (Integrated Pilot Shaft) Crankshaft. This version requires use of a bump starter or starter box and will not accept a pull start or the TRA EZ-Start system. For use in all TRA TRX2.5 and TRX 3.3 equipped vehicles with flywheel access 60% more peak power than the TRX2.5, with nearly 50% more power under the curve for strong linear acceleration One-piece IPS crank provides precise gear mesh and eliminates vibration Rear exhaust Molded LCP (Liquid Crystal Polymer) body slide valve carburetor with high-volume air filter Blue anodized aluminum cooling head with molded head protector TRA TRX 3.3 Racing Engine with IPS crankshaft, air filter, filter oil, setup DVD, illustrated instruction manual and glow plug Bump starter or starter box of modeler's choice Fuel: Car fuel blend with 10-33% nitro content Displacement: .20 cu in (3.3cc) Specs such as bore, stroke, RPM and horsepower are not provided, contact TRA for further details Weight: 9.1oz (257g) Distance between mounting holes same side: 0.43" (11mm) Distance between mounting holes opposite side: 1.2" (32mm) Distance from center of engine to front bearing: 1.2" (32mm) Distance/bottom of mounting flanges/top of cylinder head: 3.6" (92mm) Distance/ crankcase bottom to top of cylinder head: 44" (105mm) Width of mounting flanges: 1.5" (39.5mm) Other versions of the TRX 3.3 engine include; #5406 Multi-Shaft without Starter, TRAG5406 #5407 Recoil Pull Starter, TRAG5407 #5409 Multi-Shaft w/Recoil Pull Starter, TRAG5409 Some notes on slide valve and rotary carburetors. Rotary carbs offer a larger response in the middle of the power band. This works well for off-road applications when throttle response must be varied. Slide Valve carbs provide greater response at the beginning and end of the power band. This works well for on-road and racing applications for fast take-offs and high speed. jxs 2/22/06 ir/jxs &