Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HD390 found under Cylinder Head Gasol by Curtiss Wright Electro Mechanical Corporation Dba Steam And Air Solutions Div Cu. The National Stock Number assigned to this part is 2805003747477, 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 HD390.