Wilwood GM metric series brake calipers are direct replacements for 1978 and later D154-type GM metric calipers. Weighing in at a mere 2.97 lbs., they provide a substantial weight savings over cast iron OE calipers. The real strength of these calipers comes from their triple-bridge configuration, which provides higher clamping efficiency through lower deflection. The overall results are stronger, lighter, and more efficient aluminum calipers. The caliper bodies are precision-cast, using a tight grained, high-density aircraft alloy. Stainless steel pistons provide improved fluid protection with high resistance to corrosion and low heat transfer. Each caliper is fully machined, assembled with high-temperature seals, and tested in-house by expert Wilwood technicians to ensure top quality and peak performance.