There is soooo much more involved.
First of all, 1/2 a second is significant.
Second, there can be a big varience based on who the driver is and where they were (altitude, heat, humidity, traction available, and so on). It is not always a very good comparison to just take some published information and try to get concrete answers. I know from experience that a self respecting Mustand GT can do better than 7.2.
Horsepower and torque, at least how we measure them, are closely related. A dyno only reads torque. Horsepower is calculated by mulitplying torque times RPM (with a constant factored in).
Specs that show peak power don't really tell you enough. It is the power that gets to the ground that counts. If one car has a broader power band than another, and both have about the same peak power, the one with the broader power band will have the advantage.
It's late, and I'm going to bed. Someone else can add to this (or argue against it if you wish).
