The latest Thunder Tiger PRO-21/28 series car engines have been designed for one eight scale radio-controlled model cars to combine high performance with easy handling and maintenance using modern CAD computer technology. Major components of the engines are machined from the highest quality materials using state-of-the art CNC manufacturing techniques, resulting in consistently high performance and reliability. The PRO series engines are equipped with dual-ball bearings, Schnuerle porting, ABC type piston and cylinder, and automatic mixture control carburetors.