Well, having dropped a 46re on my chest, I can confidently say it's almost double that with the verter in it.

I would not doubt a significant gain using the 727 over the 518. The overdrive adds a good deal of rotating weight. I think a half second gain with the 727 is definitely possible.

I believe the power loss through a 518 was figured to be something like 23 percent if memory serves correct.