I have a friend who runs a Fox 40BB on a Dazzler. Its more than the equal of any of the OS 40's.

I have an old (but new) lapped iron Fox .40 bushing engine I've been breaking in slowly. This is one of those odd-run model they'd make occasionally. Its the 6-bolt backplate .40 guts in the large frame 6-bolt .45/.46 bushing case. Its power on a 75/25 (all castor) FAI mix with the Fox tuned pipe is very very impressive.