[Silverback51]

Well this has been fun to watch, but I guess we better straighted it out.

I'm just pulling the numbers out of my butt, however you will understand the concept.

Viper

3600 pounds with 600 HP. 3600/600 = 6 pounds per HP


Cobra

2500 pounds with 500 HP. 2500/500 = 5 pounds per HP


What this means is that the every HP for the Viper has to move/accelerate 6 pounds of mass. For the Cobra it only has to move/accelerate 5 pounds of mass.

If all other things are equal, the Cobra would win. However there are a lot of other variables that could affect the outcome.