Yes and no. 650 AVS is a very good carb. Easy to tune and great aftermarket support. I've tuned mine to get around 17 mpg. Which is pretty damn good considering the fact that I have 3.55 rear ratio, 3 speed automatic (non-lockup) and an airgap manifold.
17 mpg at 70 mph at 3200 rpm's at 4500 ft altitude. I'm happy. If was to get an overdrive setup I'll easily hit the 20 mpg mark. (Despite what some people think)
The thermoquads I've seen on some of the local power wagons and A-B-E body's here in the local mopar club i'm in has me convinced.
The only problem is getting aftermarket parts. but usually solve that problem by buying cores that occasionally show up for 30-50 bucks a pop.
