A downside of the Trophy 4 was engine vibration, as an inline four-cylinder engine suffers from inherent secondary imbalance resulting from its 180 degree crankshaft. The two outside cylinders move together simultaneously, as do the two inside cylinders. Due to the geometry of the wrist pins, connecting rods and crankshaft journals a piston descending from top dead center will always move quicker through the first 30 degrees of crankshaft travel than a piston moving upward from bottom dead center, meaning that more mass is moving downward than is moving upward, causing a shaking in the vertical plane. Modern engines larger than tend to have twin counter-rotating balance shafts to counteract these vibrations, but balance shafts were not commonly used until the mid-1970s. The Trophy 4 was instead cushioned by flexible rubber engine mounts designed to isolate the engine from the rest of the car, and its forces were further damped by the Tempest's unusual drivetrain that distributed these forces through the torque tube to the rear-mounted transaxle. The timing chain in the Trophy 4 was originally the same as the 389, but was prone to stretch and break from engine vibration; a special high-strength version was developed as a replacement. The Trophy 4 was dropped from the Tempest line when it was redesigned to a larger size for the 1964 model year.