They are the best carb out there period. I have run as fast as 10.85 in a low compression 340 NHRA G/S 1972 Demon that is at over 3300 pounds. I pulled a 1972 Duster that had been sitting in my big shop for 11 yrs dumped some fuel in the tank changed the plugs fired it up. It idles at 650 rpm starts with a turn of the key without pumping the throttle. The holley 6pack carbs I have need a full rebuild because of all the gasket shrinkage and other problems like stuck idle screws. Give me a THERMOQUAD any day!!!