Cylinder Head - Top View

Fig 1: Identifying Bolt Size & Locations On Cylinder Head - Top

Courtesy of GENERAL MOTORS CORP.

Service Call Out	Thread Size	Insert	Drill	Counterbore Tool	Tap	Driver	Drill Depth Maximum		Tap Depth Maximum
J 42385-850							MM	IN	MM	IN
1	M6 x 1	205	852	N/A	203	204	23	0.906	19	0.748
2	M6 x 1	205	201	202	203	204	20	0.787	16	0.63
3	M14 x 1.75	856	857	N/A	858	859	THRU		THRU
4	M8 x 1.25	854	853	N/A	208	209	30	1.182	27	1.063