Cylinder Head - Top 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							MM	(IN)	MM	(IN)
1	M6 x 1.0	205	201	202	203	204	23.0	0.907	23.0	0.907
2	M6 x 1.0	205	701	none	203	204	23.0	0.907	23.0	0.907