blower od on street motor

here is what I got
383zz gm crate motor 9.5 comp aluminum heads 430hp
ready for this dmpe 671 top fuel m4 we removed strips and welded damage cut rotor length and polished rotors to get clearance
I want to make 4 to 5 lbs boost and run on e85 I can handle the tune up and have some plans for a mid range

I need help where to start for under drive any ideas

 

would the charts from this article be of any help to start with(middle of page)?
http://www.jegs.com/s/tech-articles...chargers+-+Blowers+-+Roots+Type+-+Centrifugal

 

This Might or might not help you but we ran a littlefields 8/71 hi helix retro (kobelco k8 rotors)@ 7% under on a 524cui BBC and made 9-12lbs of boost @ 7000rpm,an m4 6/71 is gona make good boost if it was me I'd start a 15 under and go from there !!!!

 

20 under

I ran plenty of street stuff, I'd go 20 under to start, yeah, about 20 under.......