Don't worry so much about what the actual number is. Your right in the range you should expect and the dyno is just a tool. Your looks to see how this new mod (E85 tune) will improve over what you have now. The true test will come at the track.
EFR Twin Turbo LFX-GPI Tune-ZL1 fuel pump-10:1 CR forged pistons-3.45 gear-Meth Injection-BMR Trailing Arms, Bushings & Sway Bars-CircleD 4000 Stall-GPI Fuel Enrichment System
647 RWHP & 726 RWTQ @18.5 psi on 93 Octane (locked converter)
1/8 mile -- 7.158 @ 102.10 (20psi); old build