Pontiac Alley - Pontiac GTO Engines

Pontiac Alley - Pontiac GTO Engines

Identify the engine installed by the two number engine code stamped
on the front of the block, on the surface below the right cylinder head.
Go to the Pontiac Engines page to determine engine production date code
and engine casting number.

1964 GTO Engine Number Codes	Cubic Inch Displacement	Horsepower	Transmission
76	389	348	Man
77	389	348	Auto
78	389	325	Man
79	389	325	Auto

1965 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WS	389	360	Man
WT	389	335	Man
YR	389	360	Auto
YS	389	335	Auto

1966 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WS	389	360	Man
WT	389	335	Man
WV	389	360	Man
WW	389	335	Man
XE	389	335	Auto
XS	389	360	Man
YR	389	360	Auto
YS	389	335	Auto

1967 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WS	400	360	Man
WT	400	335	Man
WV	400	360	Man
WW	400	335	Man
XL	400	255	Auto
XM	400	255	Auto
XP	400	360	Auto
XS	400	360	Man
YR	400	360	Man
YS	400	335	Auto
YZ	400	360	Auto

1968 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WS	400	360	Man
WT	400	360	Man
WY	400	360	Man
XM	400	265	Auto
XP	400	360	Auto
XS	400	360	Man
XW	400	360	Auto
YS	400	350	Auto
YZ	400	360	Auto

1969 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WS	400	366	Man
WT	400	350	Man
WW	400	370	Man
XP	400	370	Auto
XX	400	265	Auto
YS	400	350	Auto
YZ	400	366	Auto

1970 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WA	455	360	Man
WS	400	366	Man
WT	400	350	Man
WW	400	370	Man
XP	400	370	Auto
YA	455	360	Auto
YS	400	350	Auto
YZ	400	366	Auto

1971 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WC	455	335	Man
WK	400	300	Man
WL	455	335	Man
WT	400	300	Man
YC	455	325	Auto
YE	455	335	Auto
YS	400	300	Auto

1972 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WK	400	250	Man
WM	455	300	Man
WS	400	250	Man
YB	455	300	Auto
YC	455	250	Auto
YS	400	250	Auto
YT	400	250	Auto

1973 GTO Engine Letter Code	Cubic Inch Displacement	Horsepower	Transmission
WK	400	230	Man
WP	400	230	Man
WS	400	230	Man
X5	400	230	Auto
X7	455	250	Auto
XE	455	250	Auto
XK	400	230	Auto
XL	455	250	Auto
XM	455	250	Auto
XN	400	230	Auto
XX	400	230	Auto
Y3	400	230	Auto
Y6	400	230	Man
YA	455	250	Auto
YC	455	250	Auto
YD	455	250	Auto
YF	400	230	Man
YG	400	230	Man
YK	455	250	Auto
YS	400	230	Auto
YT	400	230	Auto
YY	400	230	Auto
ZA	455	250	Auto
ZC	455	250	Auto
ZS	400	230	Auto