Most pinewood tracks are shaped something like this:
\ \ \ \_____________
But every once in a while you’ll see a track shaped like this:
___ \ \ \ \_____________
The first track has a starting gate where every car starts out pointing down a hill. The second track has a flat starting gate. All the cars start out sitting mostly flat and then head down the hill.
Usually you get better speed by putting your weight in the back because you get more potential energy from having the weight starting higher above the ground. With a flat starting gate, you can put the weight in the back, middle or front — you don’t get any more potential energy. Since the car is flat, no part of it is any higher above the ground than any other part of it.
So does it matter at all where your weight is at on a flat-gated track? Yes it does.
Your car will start off with the front heading down the slope, then the middle ends up on the slope, and finally the back makes it onto the slope. If you put the weight in front of the car, the potential energy of your car will start getting converted to kinetic energy as soon as the front of the car makes it onto the slope. If your weight is on the back of the car, then you have to wait for the back of the car to get on the slope before the weight starts helping out.
On this type of track, put your weight to the front and your call will pull get a little head start on the others. How far up front? About an inch to an inch and a half behind the front axle is good. Read about rear-weighted cars for an explanation of the science involved and why you don’t want your weight too close to either end of the car.