Engine Block - Top View

Fig 1: Identifying Bolt Size & Locations On Engine Block - 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	M8 x 1.25	210	206	207	208	209	23.5	0.925	18.5	0.73
2	M11 x 1.5	507	504	N/A	505	506	77.5	3.053	70	2.758
3	M12 x 1.75	865	856	857	858	859	13.5	0.531	12.5	0.49