Just note that cam selection is critical only at the wild hairy edge of a race engine. On a streeter any cam no larger than 280 degrees off the ramp duration shouldn't hit the dreaded surge point on a properly sized turbo.
The sizing of a turbo is quite easy, and it's more based on cubic inches and revs rather than cfm airflow through each port of the cylinder head. The 'before turbo but at stock compression' power curve can be rasied by the propsed boost ratio, and this will give the theoretical maximum power.
So if your engine is stock with about 120 hp, then with a 9 psi turbo-charger, the best power boost would be (9+15)/15, or 1.6. The power then hikes 1.6 times 120hp, or to 192 hp if all is the same and there is no heating of the intake charge. Of course, just a cam and intake and carb change could lift that to 150 hp with ease.
The normal things that help power, a lo-restriction exhast, a better intake manifold, a better, multiple carburation or better EFI, a more suitable header, more lift, and, to a limited degree, more duration, optimised ignition, will all yield more power as long as the turbo doesn't hit a surge condition.
Unless you have the flow maps of each perspective turbo you're looking at, then I'd just use revs, cubic inches, and likely flywheel hp power before boost. To use head flow figures, you'd have to run a specilised program, like the Engine Analyser, and then look for a turbo module to the program. If you talk to someone here who has flow figures on a stock head, then you'd be able to run a very good approximation of the likely peak power.
