Peak power is highest point in the curve, gain in power is the highest gain in HP anywhere in the curve when comparing pulls after mods.
Factory power, first of all, is rated at the flywheel and is PEAK power. So the Boss has 444hp PEAK at the flywheel...take out 12-15% and that is roughly the power at the wheels.
Hope this helps.
Matthew 26:52-54 / Go Pack Go!
1987 Mustang GT Hatchback - 2V Mod Swap In The Works
1997 Lincoln Town Car, PI Intake/Cams, Sofa-On-Wheels, "Fat Tony" we call it
2001 GT Convertible - D1SC / Geared / Cammed / 440wh 400wt - TOTALED 2/2019