396 Torque Specs

• Chevrolet produced their first V-8 engine in 30 years in the 1950s. Although this engine would be expanded into larger editions later on, Chevrolet had a need for larger displacement, so the 348-cu.-in. big-block engine was born in 1958. This engine was enlarged to 396 cubic inches in 1965 and as of 2010 is still seen in cars and trucks at hot rod shows and racetracks. When assembling a 396 engine, it is imperative to torque the fasteners to the correct tightness so they do not loosen from engine vibrations. The tightness of all engine fasteners should be checked with a torque wrench.

Internal Parts

• Two-bolt main bearing caps should be tightened to 95 foot-pounds, while four-bolt caps should exhibit a tightness of 110 foot-pounds. Connecting rod bolts should be tightened to 50 foot-pounds for 3/8-inch units and to 67 to 73 foot-pounds for 7/16-inch rods. The required long cylinder head bolt torque spec is 75 to 80 foot-pounds, while short bolts need to be torqued to 65 to 68 foot-pounds. The screw-in rocker arm studs require tightening to 50 foot-pounds, while the oil pump retaining bolt should be torqued to 65 foot-pounds.

External Parts

• The cast-iron exhaust manifold attachment bolts should be tightened to 20 foot-pounds. Over-tightening these bolts could crack the manifolds and cause an exhaust leak. Take care that the spark plugs tightness does not exceed 15 foot-pounds. The harmonic damper at the front of the engine should be tightened to 85 foot-pounds, and for the bell housing bolts at the rear of the engine block, a tightness of 25 foot-pounds is about right. The water pump attachment bolts should be tightened to 20 foot-pounds, and the intake manifold bolts should be torqued to between 25 and 30 foot-pounds.

Sheet Metal Parts

• The sheet metal parts on the exterior of your Chevy 396 engine are designed to cover certain exposed components and keep the lubricating oil contained within the engine block. The fasteners that attach these items do not need to be tightened as much as internal parts, as the thin sheet metal could warp and cause oil leaks. The valve cover bolts should be tightened to five foot-pounds of torque. The bolts that attach the timing cover to the front of the block need only be tightened to seven foot-pounds. The small oil pan bolts should be tightened to seven foot-pounds as well, while the large bolts should be tighter, up to 12 foot-pounds.