Description: Impala, Monte Carlo. 3.8l. Park Avenue. All models. 3.8l. LaCrosse. 3.8l. Bonneville, LeSabre. 3.8l. Lucerne. 3.8l. Riviera. Side of block, 3.8L. Grand Prix. Helps keep engine timing and fuel injection running in sync Helps provide proper alignment, positioning, and spacing for easy installation Synchronizes engine valves and pistons for excellent engine performance