We had a pinewood derby at our church and I decided to make a 1955 Chevy Pickup as my car. Turned out really nice!

Bits used in this video:
1/4" upcut endmill by Whiteside https://amzn.to/3Wd0dA0
1mm, 4.82 degree tapered ballnose finishing/detail bit https://amzn.to/3XzMlAU

To build a pinewood derby car, you will need the following materials:

A pinewood derby block (these can typically be purchased at hobby or craft stores)
Sandpaper (in various grits, such as 80, 120, and 220)
Carving tools (such as a hobby knife, Dremel tool, or if you're lucky, a CNC!)
Paint and brush
Weight (such as lead fishing sinkers)
Axles and wheels (these can also be purchased at hobby or craft stores)

Steps:
Sand the block of wood to remove any rough edges and create a smooth surface. Start with a coarse grit sandpaper (80) and move to a finer grit (120 and 220) to finish.
Use your carving tools to shape the block into the desired shape of your car.
Attach the wheels and axles to the car.
Add weight to the car, as needed, to meet the weight requirement of your specific pinewood derby event.
Paint and decorate the car as desired.

Note: It is important to check the rules of the specific pinewood derby event you will be participating in, as each event may have different regulations regarding the size, weight, and design of the cars.