Which Stroker for 400 and 7-8lbs boost on E85

Call a couple of piston mfgs and ask them what they recommend for your application. Find out how thick of a piston top they want, how far down should the top ring be, how tall should the compression height be and what wall thickness do they want on the piston pin. I don't think you'll have any problem building a 470 or a 500 inch short block with pistons that meet the specs they give you.