Kalistratov 45 One of the most well-crafted mass production engines in the history of Radio-Controlled Boat Racing power plants, and owner of many of its own World Championship accomplishment, the Kalistratov 45 (AKA K45) is back on the block. If you are looking for a quality but less expensive alternative to the competition bolt in a K45. Test Tune and Go Racing. Built to be competitive out of the box. Bore = .866" Stroke = .772" Exhaust timing = 180 degrees Intake timing = 126 degrees. Recommended carb: ROSSI 10343-46 BORE 11MM(.433”) or the SPEEDMASTER .45 SPDC-11 BORE .390”