Robin, the only fairly recent CL 40 from OS, other than the FP & LA bushed shaft model engines, is the 40 SF. TTBOMK, the FSR was never offered without an RC throttle on it.
There have been several threads about the 40 SF, and the next size larger, the 46 SF, in various forums on this site. I've never even run the one that I have, although I was anticipating having to go high rpm / low pitch to keep the air speed down.