Looks like Lingenfelter is getting around 800 bhp with an E-force supercharger on their ZL1 and Z06.
http://www.hotrod.com/articles/drag-...er-chevrolets/
Couldn't find the info on the ZL1, but here's the propaganda on the Z06. Looks like 680ish at the wheels on a built engine.
http://www.lingenfelter.com/product/L010995115.html
This data seems to fall in line with everyone else's comments on fueling.