Flywheel/Flex Plate Torque (4.8L, 5.3L & 6.0L)

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Tighten the engine flywheel bolts first pass in sequence to 20 N.m (15 lb ft).
Tighten the engine flywheel bolts second pass in sequence to 50 N.m (37 lb ft).
Tighten the engine flywheel bolts final pass in sequence to 100 N.m (74 lb ft).

Fig 1: Tightening Engine Flywheel Bolts In Sequence
Courtesy of GENERAL MOTORS CORP.