Stock 914 Club Racing motors

Vehicle Information: Model (914/4, 914/6): 914/4; Year: 1973; Engine (type, size, modifications): 2.0; Total Mileage: ?;

Im hoping to prepare my 73 2.0 for use in stock/prepared class and was wondering what can be done within the rules. I currently have webers on the motor which puts me in prepared, but i would like to achieve whatever the standard is for preparation within the motor.Any help?Bill