I bought the "Autozone special" and had nothing but problems with it also. Even had to rebuild it after I bought it because of a defective float. I ended up buying a Barry Grant Road Demon Jr., vacuum secondary, 625 cfm. I'm glad I did. Slapped it on, adjusted the idle speed, adjusted the float levels, and instantly felt like I picked up 25 HP over the Quadrajet. I think they are going for $289 (plus shipping) also. The only downside is that the carb is so beautiful compared to the Qjet you don't want to put an air cleaner on it.

G.J.
68 350 Coupe
"Can hear the Qjet legion calling Blasphemy already!"