Also about engines it depends on the class, and your level of racing. At nationals/super nationals it is every weekend of racing. Usually these rebuilds are relatively cheap $400-800 for a full rebuild. at club we run our club motor until the others start kicking us usually around 6 hours. I’d also like to remind you we usually run fourty five minutes for two racedays.
Engine blueprinting is a necessary. There are hundreds if not thousands of motor builders across the nation. Which one? Again it depends on the motor, yamahas are most likely Woltjer or Comet. Leopard or TAG is CKT and Comet. Shifter, Swedetech, CKT, there is a number of different builders across the nation.