I can tell you next to nothing about The East Main St. Explosion. This single was released at the height of the bubblegum craze in 1969 on the Fontana label. Both the band name and the music sounds like one of Kasenetz-Katz's kooky creations (along the lines of St. Louis Invisible Marching Band, Captain Groovy and his Bubblegum Army, Pattie Flabbies' Coughed Engine, Professor Morrison's Lollipop, the 1989 Musical Marching Zoo, etc.), but it wasn't. If imitation is the sincerest form of flattery, K & K should have felt very flattered by The East Main St. Explosion.
It's pretty tasty gum nonetheless.