I've also seen Pinewood Derby cars with LED headlights and taillights and thought this was a great idea, but I've never anything using the vintage headlight buckets that fit the 32 Ford Roadster.
(2) Yellow or white LEDs - Yellow for a more vintage look. Smaller LED's are easier to fit.
(2) Red LEDs - Mine had chrome rings already attached.
(2) Sharpie Markers or another brand with the correct shape.
2 part epoxy cement or clear casting epoxy
Sandpaper - Assorted grit from 320 to 2000
Pinewood Derby Kit
Coin Battery holder (I used holder and 2032 battery from an old motherboard)
(4) lengths of 2 different color wires - I used red and blue.
Hot glue gun
Soldering Iron and solder
Step 1: Create the Headlight Bucket
Drill a hole through the back of the bucket just large enough for both leads of your LED to fit through. If the hole is too small it will bend the leads together and risk a short. The markers I used had some ribs inside that interfered with seating the LED. These needed to be opened up. Drilling didn't work; the drill grabbed the ribs and made it hard to hold and deformed the bucket. Running the dill backwards seemed to push the ribs out of the way enough that the LED would seat in the bucket. A dremel might work too.
Step 2: Modify the LED
Step 3: Mount the LED
Insert the LED body into the bucket. Hold the LED to center it in the bucket and add a little hot glue to the base from the outside. The glue must hold the LED in the desired position but more importantly it must seal any gaps in the hole so the epoxy that we're about to pour in there doesn't leak out. I use a piece of polystyrene foam and stick the leads in the foam to hold them for pouring.
Step 4: Pour the Epoxy
Step 5: Complete the Lens
To paint your bucket, place the lens down on a piece of masking tape. protect the leads with a little tape or vaseline, and spray the bucket your color of choice.
At this point you can polish your lenses or coat with clear nail polish.
Step 6: Mount and Wire the Headlights
I realized the buckets were a little big to fit between the hood sides and the tires. I decided to thin the wheels, since I wasn't racing and didn't need to follow all the rules. The big n little look fit well with this car anyway.
Taillights for this car were purchased as-is at Radio Shack for a couple bucks each. They already had the chrome trim ring on them and fit perfectly. Measure the diameter of the shaft and drill a hole to fit.
I know I'll get some criticism for recommending this but here goes--the pinewood derby only lasts a few hours and you don't really need resistors. The LEDs will last longer than needed. We'll be running 4 LED's with a single 3V coin battery. If you really want to add resistors there are plenty of 'ables showing how.
Solder a thin red wire to the long leg of each LED. Use a clip for a heatsink between the solder joint and the LED to protect against excessive heat. Solder a blue wire to each short leg. Route the wires through the body through holes to the battery holder. Twist each bundle and solder the black wires to the positive terminal on the battery holder and the bundle of white wires to the negative. I used a big puddle of hot glue to fasten the battery holder to the bottom of the car.
If I made the battery cavity larger I could have made all the connections with a small perfboard for a cleaner job. Sorry I don't have pics of the underside - I'll try to add them when I get a new camera.
Place the battery in the holder and the lights should fire right away. My on/off switch is a strip of plastic from the battery packaging slipped between the battery and the clip.
Thanks and good luck!!