Friday, 18 September 2015

Exhaust Manifold Torque Specifications For Any 350

If you end headers or manifolds, all first-gen exhaust pipes snap on at 25 lb.-ft.

Claim the text "three-fifty" to anyone remotely recognized with the automotive sphere, and odds are the cardinal item they'll consider of is the fresh Chevrolet bitty block. But, this storied displacement spans three generations of Chevrolet/GM V-8: the contemporary mini block, the second-generation LT1 and the LS1 that came to exchange it in 1997.

First Generation

Bolt torques remained quite consistent from the modern small-block's introduction in 1955 until it was discontinued in 2002. The first-gen baby block uses 3/8-inch exhaust bolts and nuts with 16-pitch threads, which should be coated with anti-seize compound before they're torqued to 25 lb.-ft.

Second-Generation LT1

GM introduced the second-gen LT1 in the 1992 Corvette as a new modernize to the new baby block. The exhaust manifold heat shield bolts go on at 80 inch-pounds (not foot-pounds), the pipe-to-manifold bolts go on at 26 lb.-ft. and the manifold pipe nuts spec out to 26 lb.-ft.

Further published as the Vortec, this engine was a clean-sheet arrangement that shared not a unmarried Element with the original small block. The LS1 is a thoroughly modern engine, easily as advanced as anything on the road today and requires a whole new set of maintenance procedures. Torque the LS1's exhaust manifold bolts in two stages. Torque all of the bolts to 11 lb.-ft. on the first pass and 18 lb.-ft. on the second pass. Most of the LT1's parts exchange with its predecessor's, and bolt torque specs are coincidental. Torque the LT1's exhaust manifold nuts and bolts to 30 lb.-ft.

Third-Generation LS1