It looks like a Rupp - Dart Kart for sure, but I could not tell you the exact year. But the gas pedal & brake pedal mounts are different from most I have seen. The front bumper & bumper mount across the front of the frame are not original & was added by someone & certainly not factory. And the brake & gas pedals look like they are also aftermarket parts. Here is a picture of a Rupp - Dart Kart that has original parts but sadly I do not know what year it is either, but it is the closest version I could find a picture of. At least it helps narrow down what it is, I just can't say what year it happens to be.