New from HPI are Aluminum Clutch Shoe Sets for big block engines. Made from purple anodized aluminum, these clutch shoes are more durable than stock clutch shoes for longer clutch life and longer service intervals. The alloy clutch material is also more stable at high operating temperatures, making them an excellent upgrade for high horsepower engines and extreme driving conditions. Available in 2-shoe and 3-shoe designs to fit the different flywheels made for the Savage line of trucks. Each set comes with two different spring types, silver is recommended for the Nitro Star .25 engine while the gold springs are suited for high horsepower applications like the K4.6 engine. The set comes with adjustable screws for each shoe, allowing further user customization based on track conditions and driver preference.