The dripper's where to help oil the rocker arms as the higher HP engines had higher lift cam and heavier valve springs.
The higher pressures of the solid lifter valve springs put more pressure on the rockers and pivot balls and the manufacturers and aftermarket came up with various ways to improve the oiling there the drippers were a great idea,grooved rocker balls were another example.Chevy wasn't alone in using them from the factory,Ford and Pontiac used them also and there may have been others too.Pontiacs used a few different variations over the years.Chevrolet installed them on most engines that left the factory with solid lifters, they accumulate oil and it drips off the point onto the rocker arm near the valve stem. Only the HP 409’s had them, hold onto your wallet when you buy a pair as everyone is proud of them.