REFLECTOR: Alternative engines

[Tom]

Velocity owners/builders tend to be an outside the box group. 
Proportionately speaking, I see a lot of Velo builders opting for 
engines other than Lycoming/Continental/Franklin. Has anyone tried to 
figure out what the success rate is on the outside the box engines? Do 
you have to reinvent the wheel on the installs? Are there reliability 
issues? How hard to work out the bugs (cooling, fit, gear reduction, 
etc)? Are any cost or efficiency savings promised actually realized and 
worth it? Tom