HP = total weight * 200 / ET 3 (that would be cubed). For this formula to work, you need to get a drag strip ET.
For instance: a 2800 lb car with 200 lb driver, runs a 10.00 sec. ET. The horsepower at the rear wheels would be about 600. This assumes proper overall gearing, no wheel spin, a good racing type torque converter, and so forth.
NOTE: This very old formula does NOT work well with very light vehicles (such as motorcycles), nor with vehicles with great amounts of horspower, such as blown nitro drag cars (Top Fuel and Funny Car). But, it'll be dead-nuts on for your big block powered Camero bracket racer, or a Pro Stock Chevy or Dodge
I just ran the figures for a Pro Stocker and came up with a little over 3 hp per cube. Not bad for a 500 cubic inch push rod engine with carbs and burning gasoline.
