There should be a bunch of ideas on this one. From what I know and I'm sure I'll be corrected here if I'm wrong, the differences are in pumping losses due to less crank deflection on the different crank throws. There are some builders who find power there, others who find smoothness within a certain rpm range. Some find nothing. I think a ton of the "found power" has to do with getting the precise cam to match the head and rpm combo. If that is not already perfect, I don't think you'll see a gain. Personally, I don't see much of a bonus in it and I never bothered. But, for some in certain circumstances due to class restrictions or whatever, they may find it helps. The only thing that needs to be changed is the cam from what I know. Which is arguably limited.