Well, my car came with a dual quad set up on a 440 High Performance. It was a dealer installed set-up that the original owners had installed before every taking delivery of the car.

It "was" two Carter AFB's in line on a single plane manifold. Basically the same intake set-up as on the 62 300 H. It operates off a progressive linkage and the front carb is the primary and has the choke and idle speed screw. I've been experimenting with tuning. The front carb went bad and I had it replaced with an Edelbrock Performer (~~600 CFM).

For the most part, both drivability and power are both pretty good. I'm still not convinced I have the carbs set up perfectly. I can tell you this, It starts and runs nice in both hot and COLD weather without any stalling or other issues. Power is pretty good, especially when the throttles are wide open and car reaches high and SCARY speeds pretty darn quickly.

Fuel economy is not too bad. I have gotten as high as 14 but usually it is about 11 or 12 mpg.
The car is a 67 Chrysler 300 'vert (pretty heavy) with torqueflite and 3.23:1 Sure Grip diff.