The Daystar 80MHz PowerPro 601 has a 20MHz oscillator to run the processor at 80MHz. The card is designed to run on the Centris 650, Quadra 650, 700, 800, 900, and 950's at their normal 25 or 33MHz speed. They do not work when these machines have been clock chipped to 40MHz.
So... to speed them up, simply replace the 20MHz oscillator with a faster one. Take a look at Modification 1. With a 21.47727MHz oscillator the card runs at 85.90908MHz. The card did not work with a 23.587 or 24MHz oscillator.
That's all the info I got from the guy who e-mailed me. Let me know if you learn anything more.