Cylinder Head - Exhaust Port View

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: View Of Cylinder Head Exhaust Port

Courtesy of GENERAL MOTORS CORP.

Service Hole Location	Thread Size	Drill	Counterbore Tool	Stop Collar	Tap	Driver	Insert	Drill Depth (Max)		Tap Depth (Min)
mm	(in)	mm	(in)	-	-	-	-	-	-	-	-
1	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
2	M 10 x 1.25	not serviced						80	3.15	30	1.181
3	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
4	M 10 x 1.25	not serviced						80	3.15	30	1.181
5	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
6	M 10 x 1.25	not serviced						80	3.15	30	1.181
7	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
8	M 10 x 1.25	not serviced						80	3.15	30	1.181
9	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
10	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
11	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827
12	M 10 x 1.5	211	212	N/A	213	214	215	25	0.98	21	0.827