Engine Block- Back View

Fig 1: Identifying Bolt Size & Locations On Engine Block - Back View

Courtesy of GENERAL MOTORS COMPANY

Service Call Out	Thread Size	Insert	Drill	Counterbore Tool	Tap	Driver	Drill Depth (Maximum)		Tap Depth (Maximum)
EN 42385-850							MM	(IN)	MM	(IN)
1	M8 x 1.25	210	206	207	208	209	18	0.709	THRU
2	M10 x 1.5	215	211	212	213	214	29	1.161	THRU
3	M12 x 1.75	855	856	857	858	859	39	1.535	33.5	1.32
4	M16 x 1.5	860	861	862	863	864	21	0.827	15	0.59