These big-bore kits have been race ported by ESP (Earth Surfer Products) - intake, exhaust, and transfer ports have been enlarged/reshaped for more fuel/air flow and hence more power. Complete 36mm GP290 big-bore kit. Now featuring improved cylinder plating for increased durability. Includes 36mm cylinder, piston, piston ring, piston pin and two pin washers, circlips, cylinder gasket, two cylinder bolts, insulator gasket, and CMR7H spark plug. Increases displacement to 28.5cc when used with a stock crankshaft with 28mm stroke. Increases engine power SUBSTANTIALLY - estimated engine power output after installation is 4 HP! This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. This kit has the 38mm cylinder skirt and is compatible with crankcases with 38mm top openings. Fits Zenoah G23LH / G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC / GP290 engines. Also works as a complete replacement top-end for the GP290 engine. This is a direct bolt-on kit for HPI Baja, Losi 5ive/DBXL, Redcat, etc.

DDM strongly suggests the use of a higher quality head gasket (see ca321 and ca325)