This is a slightly modified version of reddadsteve's brilliant model of Wile E. Coyote that has been resized to fit the dimensions of a pinewood derby car. I've taken a few stabs at this and failed every time…and I can't say that I can recommend that anyone actually print and build this model. Not because there is anything wrong with the original model, but because, by sizing it down to 56% of the original size, I made it extremely difficult to put together, especially the tiny parts like the blacks of the eyes and the toenails.
But, hey, I managed to build it myself, so I proved it can be done. If you're up for a challenge, you want a pinewood derby car that is truly unique, and you don't mind losing the race (no way will this thing go fast enough to win), go for it!
I've included reddadsteve's original instructions in the Documentation.
The pinewood derby is an event created by the Boy Scouts many years ago. Each scout is given a pinewood derby kit typically consisting of a block of wood with slots for axles, 4 wheels, and 4 nails to be used as axles. The scout (and his dad, usually) will then carve the block of wood into the shape of a car, paint it and apply stickers, install the wheels on the axles, and then race it at the "derby", which involves a sloped track with a timekeeping apparatus.
An official scout derby will usually require that the parts in the kit be used for cars entered in the derby. Other organizations (including workplaces) often hold derbies, too, and some of them require the use of the parts in the box, including the block of wood.
These "pinewood derby car shells" are intended to be used with an official derby wood block, cut down to size, along with the axles and wheels included in the kit. A printable model of the shaped wood block is provided. You can either use the printed model or use it to accurately cut an official wood block down to size.
Notes:
Just super glue all the parts together.
You can add tungsten weights to the holes in the back of the base to end up right at 5 oz. Playing with different infills and weights can get you close to the ideal front/rear balance.