Whipple 510 Twin Screw

I'm interested in putting a 510 Whipple on my 565 cu.in Boss motor. Does anyone have experience (or own) a big block ford with a whipple supercharge? I'd like to know, from real world experience, the benefit it has over a 10-71 roots blower? On pump gas, 91 octane, how much incremental boost (performance) can I get from the whipple twin screw technology? Also, are the roots and whipple drive systems inter-changeable?

If you are an engine builder and have built such a combination, I would be interested in talking with you...I have money to spend.