[bkozlow]

During the 60-70's the major car manufacturers added to their carb setups a thing called a DASHPOT valve. This is basicly a vacuum operated plunger. The valve is attacted to the carb at the left front carb stud. It is a vacuum diaphram, a line connected to a vacuum port on the carb and on the other side an adjustible bolt. This bolt then moves as vacuum in the engine changes. The purpose of this was to cushion the last 500 RPM when the throttle closed quickly. One of the problems with carbs is there a lag in its ability to react to changes in throttle position. The dashpot slowed the final closing of the throttle so the carb could catch up with the new leaner running position. Look at any Holley of the 60-70's on an automatic and as well as some manuals and it will definitely have a dashpot valve.