Let's see if we can clear this up: Finer pitched gears transfer power more efficiently than coarse pitched gears, much like a fine threaded 1/4" bolt torques more smoothly than a coarse threaded 1/4" bolt.
There are friction losses in all mechanical gearing; the finer the pitched gears the less frictional loss there is, so:
given a 1.3 HP engine, and fine pitch gears with 95% efficiency and coarse pitched gears with 90% efficiency, the fine pitch gears will transfer 1.3 x .95 = 1.235 HP, and the coarse pitch gears will transfer 1.3 x .90 = 1.17 HP.
Can you realistically see the difference? Probably not while racing, but in a side-to-side shootout you may be able to. If you couldn't realize a difference then why do people lay out big bucks for replacement bearings, CVD's, low friction belts, etc...... it's because it's all about reducing friction all around the car. 5% from the gearing doesn't seem like a lot, but if you then get 3-5% from the bearings, 3% from the CVD's, 3% from the belts, all of a sudden you've got 14-16%!! You do the math.....and see if you think that amount will make a difference.