This is for One Used 1966-1967 Corvette Fan Clutch Eaton Big Block Dated H16F Aug 16, 1965 cant really easily see the CK code maybe 20 years back it was visible. GM# 3916141. This due to the August 1965 date code is most proper for early 1966 Corvettes, September October and even November 1965, Big Block 427 Eaton fan clutch.