This is a "Camshaft Button" for a 1986 or 1987 Buick Grand National, T Type, Turbo T, or GNX 3.8 liter turbo V6. This is highly recommended to change out on every camshaft, this is a needle bearing button where as the factory button is a plastic piece. This keeps the valve train running smoothly, and does not allow the camshaft to walk forward or backward.
