Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R520142 found under Insert Engine Valve Seat by Western Diesel Services Inc. The National Stock Number assigned to this part is 2815015485620, and the Federal Supply Class is 2815 Diesel Engines And Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like R520142.