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70 GTO 400-4
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Pontiac MuscleCars - 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.


Pontiac V-8s

1964 GTO Engine Number CodesCubic Inch DisplacementHorsepowerTransmission
76 389 348 Man
77 389 348 Auto
78 389 325 Man
79 389 325 Auto

1965 GTO Engine Letter CodeCubic Inch DisplacementHorsepowerTransmission
WS 389 360 Man
WT 389 335 Man
YR 389 360 Auto
YS 389 335 Auto

1966 GTO Engine Letter CodeCubic Inch DisplacementHorsepowerTransmission
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 CodeCubic Inch Displacement HorsepowerTransmission
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 CodeCubic Inch DisplacementHorsepowerTransmission
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

1974 GTO Engine Letter Code Cubic Inch Displacement Horsepower Transmission
WP 350 200 Man
YS 350 200 Auto
YP 350 200 Auto
ZP 350 200 Auto

Go to the Pontiac Engines page to determine engine production date code and engine casting number.

GTO VIN 64   GTO VIN 65   GTO VIN 66   GTO VIN 67
GTO VIN 70   GTO VIN 71   GTO VIN 72   GTO VIN 73  
GTO VIN 68   GTO VIN 69
GTO VIN 74   GTO VIN 04-06


Pontiac GTO/GT-37 Illustrated Identification Guide!
Pontiac GTO/GT-37 Illustrated Identification Guide!


Pontiac Magazines:
  • High Performance Pontiac - High tech and massive muscle cars.
  • Pontiac Enthusiast Magazine - GTO, SD Catalina, Trans Am and Grand Prix GTP.

    Pontiac Resources:
  • Classical Pontiac - Chat, Classifieds, Clubs, Events, Features, Links...
  • GTO Association Of America - Mission is to preserve and promote the Pontiac GTO.
  • The New GeeTO Tiger - Check out The Jim Wangers Collection.
  • Mast Motorsports - The Power and Engine Innovators.
  • Pete McCarthy - The Pontiac Bible.
  • Pontiac Historic Services - Pontiac VIN number information.
  • Pontiac Mall - Look for Pontiac Apparel!



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