Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3870E57 found under Flange by Kenworth Truck Co. The National Stock Number assigned to this part is 2520003532711, and the Federal Supply Class is 2520 Vehicular Power Transmission Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 3870E57.