If you're planning on using that much nitrous, you're going to need to use direct port injection. A single nozle wet shot that large in the opel manifold would likely cause a small explosion and destroy your carb. There was a web site that I found once that detailed how to build your own direct port nitrous system using parts available from Radio Shack. Do a google search for Nitrous do it yourself and motorcycles (he drag raced motorcycles). Good luck.