HiPo cylinder head

C5AE-E heads are HiPo heads with 54.5 chamber, 1.78/1.45 valves.

Decoding of the casting number reveals:

C - Decade - 1960s
5 - Model Year 5 - 1965
A - Car line - Full size/Galaxie
E - Engineering department - Engine

Date code 5E5 indicates that the heads were cast on 5 May 1965.