Where did you buy the carb & was it new? That's the time to be asking your questions. If new, information should have been provided with the carb explaining if it was for street use or for strictly off road & if it complied with emission requirements. Laws can vary in different places, but usually if it's a "trailer queen", it's exempt from emissions and other public highway ordinances. But, it must be operated off of the roads that these laws affect & some kind of ATV or other off road tags or registration must be displayed. For example, here, in Oregon, if you want to run your street 4 x 4 in the off road parks, you must get an ATV permit and display the sticker on the rig, just as if it were an ATV or other trailered rig. The permit is honored in most off road parks out West.