Using modern (more or less) parts, you can get a double ended Sportster coil to fire 2 sparkplugs at once. Many of the antique radio parts suppliers sell an electronic car radio vibrator that you can use to tickle the coil. Back off the throttle, maybe pull the choke a bit and hit the kill switch, and you can spout more flame than Old Faithful does water.
Speaking of water, if you use that for Dinguas smoke screen, it is harder for them to give you a ticket. The 2 things you are allowed to discharge on the highways of the US from a moving vehicle are "plain" water and live chicken feathers.
