If you want to know your Horse Power or 1/4 mile time, get your vehicle dyno'd at a shop or take it to the track. If you are bored online and would like to theoritically know where you stand, check out this MPT Online Dyno Calculator.

For this First one, we'll guesstimate how much horse power you've got at the wheels using your vehicle's weight and how fast you were able to get going during the 1/4 mile.
Enter your vehicle's weight in pounds:
Enter the 1/4 mile Trap Speed you made in MPH:
Survey says... Your Estimated Horse Power at the Wheels is:

For this Second one, we'll guesstimate your 1/4 time and how fast you can get going using your vehicle's weight and horse power at the wheels.
Enter your vehicle's weight in pounds:
Enter the Horse Power you've got at the wheels:
Survey says... Your Estimated 1/4 Mile Time is:
and your Estimated Trap Speed in MPH is:

Here's some more interesting info and calculations:
Horse Power = (Torque x RPM) / 5252
Torque = (5252 x Horse Power) / RPM
RPM = (5252 x Horse Power) / Torque
Horse Power = Weight x (Speed/234)^3
Horse Power = Weight / (ET/5.825)^3