This is the Axial .32 Spec 1s Racing Engine with Grey Cylinder Head, Pull Starter and SG (pilot) Crankshaft. Direct bolt-in replacement engine for any .21+ engine mount, also accepts most aftermarket shaft drive starting systems. FEATURES: ABC cylinder construction-"A"luminum piston,"B"rass cylinder liner that is "C"hrome plated Composite bodied 9mm (including 8.0 & 8.5mm optional venturis) 3-needle slide valve carburetor, factory reset line on high-speed needle and flush needles make resetting to factory specs easy SG (pilot) crankshaft with long duration intake Eight-port cylinder sleeve High volume transfer port design Removable button type combustion chamber Roto-starter available optionally INCLUDES: Axial .32 Spec 1s Racing Engine with Grey Cylinder Head with pull- starter One Instruction Sheet One 8mm Restrictor One 8.5mm Restrictor REQUIRES: Glow Plug: Cold heat range Fuel: 20-30% With at Least 18% Oil Content Manifold and Tuned Pipe (Depends on Vehicle) SPECS: Displacement: .32 cu in (5.2cc) Maximum RPM: 34,000 Bore: 19.5mm Stroke: 17.5mm Weight: 450g (15.87oz) Distance Between Mounting Holes Same Side: 21.10mm (0.830") Distance Between Mounting Holes Opposite Side: 36.97mm (1.455") Height Bottom of Mounting Tabs/Top of Cylinder Head: 97.55mm (3.84") Width of Mounting Tabs: 44.98mm (1.770") Distance from Pull Starter to Front Bearing: 83.38mm (3.28") Distance from Center of Engine to Front Bearing: 41.69mm (1.641") Distance from Center of Engine to Pull Starter: 41.69mm (1.641") COMMENTS: 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.