Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 8663-A-304 found under Block And Tackle Set by L 3 Communications Essco Inc. The National Stock Number assigned to this part is 3940014113662, and the Federal Supply Class is 3940 Blocks Tackle Rigging And Slings. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 8663-A-304.