Higher compession supercharged V8

[gluon]

I am building a 6-71 blown 402 inch (4"x4") aluminum small block. With a water/air intercooler so i should end up with 12psi of cool boost. I want to run a good amount of straight water controlled by the load reading on my efi computer.

What compression can i get away with? 10:1? Flowrates? I have no experience with water injection.

High much compression you can run really is dictated by a number of variables, one of the key ones how much ignition advance are you going to run. The other things in the equation are:

Octane of the base fuel
Amount of water sprayed( and a strong enough ignition to fire it)
Boost levels and IAT
Efficiency of the combustion chamber( are you starting with knock-prone chambers)

Anything is really possible if you get the combination right.