Engine Block - Bottom View

Fig 1: Engine Block Thread Repair - Bottom View

Courtesy of GENERAL MOTORS CORP.

Service Hole Location	Thread Size	Drill	Counterbore Tool	Stop Collar	Tap	Driver	Insert	Drill Depth (Max)		Tap Depth (Min)
J 42385-400								mm	(in)	mm	(in)
1	8 x 1.25	206	207	n/a	208	209	210	30	1.182	25	0.985
2	10 x 1.5	417	n/a	n/a	418	419	420	53	2.088	45	1.773
3	20 x 16	n/a	n/a	n/a	n/a	n/a	n/a	33	1.300	23	0.906