Anyone used an Annular venturi ring carb? how's it run?

[Gremlingts@xxxx]

 My friend John Young mentioned that a Mopar 2-bbl carb with an Annular 
ring-designed venturi was the way to go, very efficient and a good carb. Has 
anyone else used one, and what model/year Mopar did it come off of? I'm 
thinking of getting one or two, as I'm NOT impressed with the AMC carbs at 
all now, poor response, leaks alot, etc. Thanks for any help/leads