Dual quads. Even at idle my engine seems to like it better than any Holley or Demon. I running them 1 to 1 now, even got better yet. You don't need rpm, it idles great like Carters/Edel carbs and has kick butt power like a holley. I took the air door out of the front cars and lengthen the primary pump shot so fuel comes on out all the way to WOT. No bog with a 3,000 stall and 3.91 gears. I would never go back to one carb