I am getting to the party late, but there is no way I would use Keith Black pistons. You can get a much higher quality off the shelf piston with ICON and they have a lot of SBM options.
I didn’t recommend KB pistons I just grabbed the very first post in the 11.20 area to show how easy 450 horsepower is to make. Unported Edelbrock heads too that flow 255-260cfm compared to 300