Adding a flame thrower kit to the exhaust of your classic cruiser is an ideal way to grab attention. Kits can be purchased online, but you can do it yourself in the driveway or garage without too much hassle. These kits only work with older vehicles with carburettors and no catalytic converters. Keep in mind, throwing flames out of the exhaust is illegal in many places.
Drill a hole in the exhaust tubing. Measure in from the tip of the exhaust (back of the car) about 1.2 cm (1/2 inch). Drill a hole big enough to fit a spark plug. Depending on what plug you use, this hole can vary. It is recommended to get the spark plug first. Also recommended is to use a titanium-nitride-coated drill bit, which can be found at any hardware store. These bits are specifically meant for metal applications. If the vehicle has dual exhausts, and you plan on throwing flames from both sides, repeat this step for the other exhaust pipe, as well. Install the plug by screwing or tack welding it in.
Install a toggle switch in the passenger compartment where it can be reached from the driver's seat. Ground the negative (-) side of the toggle switch to the chassis of the vehicle and run the positive (+) side to the battery or a hot wire in the fuse block. The extra terminal will be used to wire to an ignition coil, so run that wire toward the back of the vehicle.
Install an ignition coil (you can find one at the junkyard for little to no cost) near the spark plug. Recommended is to put it in the boot if the vehicle is a car or the bed of a pickup. Wire the positive (+) side of the coil to the extra terminal of the toggle switch, and the negative to the chassis. Mount the coil using a coil bracket, which can also be found in any scrapyard.
Connect a spark plug wire from the coil to the spark plug. This will enable the spark plug wire to actually spark. Since spark plugs do not work off of 12 volts like the rest of the car, it must be connected to the coil.
Apply the choke to the carburettor slightly. Rev the engine with the toggle switch on. This will overload the engine with fuel and send raw gas fumes down the exhaust pipe, where the spark plug will ignite them and create a flame.
This set-up could be dangerous and is illegal in many places. Never throw flames when in front of another vehicle.