Chevy 8.1 Engine Exhaust Manifold Torque Specsby Robert Tomashek
Large-displacement gasoline engines, such as your 8.1-liter V-8, can produce great power without the noise of a diesel. The 8.1-liter produced 340-horsepower and 455 foot-pounds of torque, and was available in the heavy-duty General Motors trucks from 2001 until 2006.
Using a torque wrench, tighten the center bolt to 26 foot-pounds. Working from the center bolt outward -- alternating from one side to the other -- tighten the nuts to 12 foot-pounds.