As davidpozzi mentioned, the July Hot Rod has an article on Qjets. However, what I got from the article was that these carbs are very difficult to set-up, but once dialed in, they are very good carbs. You may want to consider sending your carb to the company that worked on the carb in the article.
Pontiac used the 840 cfm version of the Qjet on the SD-455 in 73-74. This engine was rated at a lowly 360hp, but with over 500 ft-lbs of torque. I understand these engines were significantly underrated (where have you heard that before?) and were closer to 450hp. So, the Qjet can be used in a very high performance application.