Pontiac stamped a variety of codes on the front of the engine block. The first code, located near the passenger side cylinder head, is the motor unit number This number was stamped at the engine assembly plant and it has no correlation to the Vehicle Identification Number. Just below that is the two-digit engine type code. A few inches farther down, near the timing chain cover is a code identifying teh Pontiac division of General Motors, the model year, the vehicle assembly plant, and the last six digits of the VIN number. On the 6 cylinder engines the code is located on the cylinder block below the spark plugs.

Engine Numbers
123456	Motor Unit Number
WH	Engine Type Code
20N 100001	Engine Vin Code
Engine Vin Code:
2	Pontiac Division
0	Model year
N	Assembly Plant
100001	Last six digits VIN

Engine Codes	Cylinders	CID	HP	Comp. Ratio	Carb	Trans
WH	8	400	370	10.5:1	4bbl	Manual
WS	8	400	345	10.5:1	4bbl	Manual
WT	8	400	330	10.25:1	4bbl	Manual
WU	8	350	255	8.8:1	2bbl	Manual
WW	8	400	370	10.5:1	4bbl	Manual
XN	8	400	370	10.5:1	4bbl	Automatic
XP	8	400	370	10.5:1	4bbl	Automatic
XX	8	400	265	8.8:1	2bbl	Automatic
YS	8	400	330	10.0:1	4bbl	Automatic
YU	8	350	255	8.8:1	2bbl	Automatic
YZ	8	400	345	10.5:1	4bbl	Automatic
ZB	6	250	155	8.5:1	1bbl	Manual
ZG	6	250	155	8.5:1	1bbl	Automatic

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This Home Page was created Thursday, April 10, 1997
Most recent revision Friday, January, 31th, 2003