What's your car weigh?
Typically GN's weigh in at 3800lbs. depending on options/mods. I calculated power based on 3850lbs. for the GN (fuel/driver) and got:
Simple Horsepower Calculations
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Using the ET method, I come up with 399 horsepower
Of couse this says nothing about torque, which dictates alot in 1/4 mile racing.
http://www.dsm.org/tools/calchp.htm