Today I cut the excess wood away with a band saw. I could also saw this by hand, and that is where it really helps to have a pattern glued to both sides of the block. Allowing me to check both sides periodically to keep from cutting into the car.
Carefully trimming down to the outline...
I take a small sanding block and smooth down the saw blade marks. Now it's a "square" body.
Draw a center-line completely around the car. This line is exactly half-way between each side. One way to do this is by taking a small strip of paper cut the same width as the car, fold it in half to get a center point, use this home-made ruler to transfer many points to the wood with a sharp pencil and using a flexible straight-edge, connect the dots. I can shoot some photos of this process if it's not clear.
