Online Horsepower Calculators

The Bottom line is if you have a car that has a reasonably good chassis that can hook, a loose-ish converter and a sensible gear/tyre combo with a motor thats set up well and runs strong you can use the Wallace calc to your advantage as a good tool for predicting its on track performance. The numbers given from your input data will be for an optimum run, and any differences from those figures against your actual time slip is where you can work out where your car is lacking, but you need a good understanding of how a Drag car works,

Here's a good example of 2 Camaros that run over here in the UK and how 1 differs from the other in the chassis dept, both have roughly the same hp.

1 is a '68 Camaro Bracket car with a 441ci SB, the other is one of the few legal "Stock" class cars we have.
The bracket car runs 9.79@137 mph with a 1.41 60ft, Wallace says that is spot on except for the 60ft which should be 1.36 so the car is down on the chassis side but the hp is there with good mph, its got potential to ET better.

The Stocker is a '69 with a 427BB and runs the same 9.79 but only at 135 mph with a 60ft of 1.27, way faster than Wallace predicts for that ET (1.36), the power is still there but its a far harder launching car which gets up the track further quicker technically has less track to build as good a mph, its maxxed unlike the bracket car. So, don't expect your street car with 2.76 gears a stock converter and treads to match anything ET wise that Wallace will come up with for your weight/hp figures, hp means nothing if you haven't got the chassis to convert it into a good ET.