RE: Shrike 10
For what it's worth, I was getting over 20K with a 7x6 Taipan using a Magnum .28XLA, no carb (wide open, bladder tank), retimed crank, no muffler/pipe. No broken cranks, either, ran it about a dozen times in that configuration before I converted it for Speed Limit Combat (75mph). Tough little engines (and cheap!).