Chrome Tappet Block Covers for Harley-Davidson Evolution Big Twins 1984-99 Chrome Tappet Block Covers for Harley Evo Big Twins 1984-1999 Clean up the look of your bike with some extra sparkle.This tappet block cover is triple plated chrome and install in minutes. No need to remove pushrods for instalation. Fits Harley-Davidson EVOLUTION BIG TWINS models 1984-99 *Product ID = 353