Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number W37-33 found under Tappet Engine Poppet Valve by Stanadyne Chicago Div. The National Stock Number assigned to this part is 2805003582939, and the Federal Supply Class is 2805 Gasoline Reciprocating Engines Except Aircraft And Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like W37-33.