screwblown smallblock need some input

this all started in the FABO chatroom maybe one year ago talking some about my plans to build a much meaner smallblock for my duster using alot of exotic stuff,well that never got built i was still planing it when my old motor died and i kind of had to do something with what i had and thats when i realised it was alot better to do what was suggested that night in the chatroom, so here is about where i am right now building a little 340 to be run on pumpgas
with a supoercharger that i kind of found for the right price at the right time :)hopefully this will be enough to outrun my friends 11.6sec malibu and have alot of fun

8.1:1compression with forged trw pistons and stock forged crank, eagle H-Beams.
some nicely ported edelbrock rpm heads
small sollidroller cam its a compcams extreme energy cam 242/[email protected] lift .570"/.576" lift not perfect but this is the remains and some other sparebits after a normaly aspirated 340 that left the building so to speak..
the supercharger is a lysholm twinscrew that displaces 3.3liters.
headers will be some way to small 1 5/8"step 1 3/4" headers with 3" collectors but they will be changed later on

how much power will this thing be capable of?
and do any of you have any input on how to calculate the boost and what size pulleys to use? first time doing a blown motor and learning as i work with it..
also this supercharger has a dominator flange boltpatern what size carb would be recomended? i have easy acces to a 750dominator and i can probably find a 1050cfm for a good price but cant realy aford a new carb at this point but maybe later, do i need to make any mods to a dominator to make it work on a blower?

this is for my 73 duster with 3.91:1 gears and a converter that stalled about 3500rpm behind a NA smallblock will run on 275/60 dragradials, nothing is even close to perfect but its all i have right now and cant do much about it but will update and improve as i learn and find the money for it.
also what kind of performance am i looking at?

thanks