The head casting number can often be found on top of the center exhaust port. In some cases it may be located on one of the end exhaust ports. These are usually easy to read by looking down from the valve cover. On some heads you may have to remove the valve cover to find the entire casting number and or the casting date.

1964 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
4-BBL	9770716
3X2	9770716

1965 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
4-BBL	9778777
3X2	9778777
Replacement	093

1966 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
4-BBL	093
3X2	093

1967 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
2-BBL	9788064
4-BBL	670
Ram Air	97

1968 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
2-BBL	9792266
4-BBL	16
Ram Air I	37
Ram Air II	96

1969 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
2-BBL	9792266
4-BBL A/T	62 or 16
4-BBL M/T	48 or 62
Ram Air III A/T	48 or 16
Ram Air III M/T	48
Ram Air IV	722

1970 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
4-BBL A/T	13
4-BBL M/T	12
Ram Air III(All)	12
Ram Air IV	614
455 H.O. (All)	64

1971 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
400 4-BBL (All)	481196 or 96
455 4-BBL	481776 or 66
455 H.O.(All)	481197,197,191

1972 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
400 4-BBL	486073,7K3
455 4-BBL	486075,7M5
455 H.O.	486076,7F6

1973 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
400 4-BBL	488543,4X
455 4-BBL	488541,4X
455 4-BBL	494341,4X

1974 GTO Cylinder Head Applications & Casting Numbers

Application	Casting Number
350 4-BBL	494345
350 4-BBL	494346