the same set up on a 496 and had same problem when i changed to an a2000 pump due to running lean moved my 10 to return and ran a 12 supply make sure you boost refrence is ran from the hat and and your blowoff is ran to the bottem of the carb or intake. I read my boost at the hat making 16lb 960 hp on chassis dyno 8.87 at 154 mph