I suspect the dyno that it made 800 on read high, but no worries. It went 137 on pump gas (making 600 on the same dyno), so I’m sure the additional WHP from the race/E85 will put it deep into the 140’s.
And yes, I’m a firm believer that you can do MORE on E85 than C16 or any other similar fuel, as long as your fuel system can support it.