It's basically an oscillator with a multiplier, the circuit is very simple. The tricky bit is the mechanical design for the clipping.
There are a few other approaches to overclocking Quadras, there are a number of threads here discussing it. Usually people will solder on a new oscillator, but some models will overclock with some jumpers/resistors. There's also the 'spicy o'clock' device which is functionally similar to the clips.
Which Quadra do you have? The 650/800 is one of the easiest to work with and most studied.