Oh and I never said they multiply power. 
Neither did I..
A 500 HP engine will make 500 HP regardless of what gear is behind it. It doesn't know the difference. If it also has 500 lb/ft torque, it will also make 500 lb/ft torque regardless of what gear is behind it. As has been said repeatedly here, "gears multiply torque". On this point, we all seem to agree. This is the torque delivered to the rear wheels via the assistance of the steeper gear and not an increase in torque output of the engine. A steeper gear allows the engine to get into it's power band sooner on launch and every subsequent gear change. Some of the newer computer controlled cars will really slow down of they get a little too much gear. When you over gear those cars, they get into the overdrive too soon and really lay down on the top end. Our old carb cars respond well to a little more gear. I ran some calculations yesterday on what would be the optimum gear ratio for the Beast to run the fastest quarter mile. With my vehicle weight, horsepower, tire size, and a couple of other factors figured in, with No other changes except a ratio change the optimum would be 4:72 to 1. I am currently running a 4:10, so there is room for a quicker ET with only a gear change. I wouldn't run a 4:72 on the street, but no more than I drive the car, a 4:56 might be in the plan one day.......
