I guess it would hurt your exhaust hehe ..... but u can do it without a spark plug ... i dun o how ... but i guess u get flames when the engine just cant burn all the fuel quick enough and it jsut gets shot out hehe ... i made a saab 9000 spit flames ... but huh thats cos i messed up the firing order on the dizzy cap so it would go splutter then bang lol flames
put it wold not move hehe ...