In the late 1950s, the Chevrolet division of General Motors decided it needed a larger displacement engine as a companion to its small-block engine, which debuted in 1955 Chevrolets. In 1958 the "W" block V-8 engine was born. This engine expanded in size over the years as vehicles became bigger and more power was needed in the late 1960s. The 454 cubic inch W block, or big block, was the largest displacement engine that Chevrolet had offered up to that point. When rebuilding or repairing a 454 V-8, it is imperative to tighten the bolts that attach the engine components to the correct torque rating. This keeps the components from coming loose under engine vibration, and keeps the bolts from stripping and damaging the threads.
All internal engine component bolts should be lubricated with motor oil before assembly. Main bearing cap bolts should be tightened to 110 foot-lbs. Connecting rod bolts should be torqued to 50 foot-lbs. for 3/8-inch rods and to 70 foot-lbs. for 7/16-inch rods. Long cylinder head bolts should be tightened to 75 foot-lbs., while short cylinder head bolts should be tightened only to 65 foot-lbs. Rocker studs should be tightened to 50 foot-lbs., while the oil pump retaining bolt should be torqued to 65 foot-lbs. The threads on the upper and lower cam sprocket bolts should be coated with a thread locker and tightened to 20 foot-lbs.
The threads of the intake manifold bolts should be coated with a nonhardening sealer and tightened to 25 foot-lbs. The threads of the exhaust manifold bolts should be coated with an antiseize compound and tightened to 25 foot-lbs. Spark plugs need to be torqued to 20 foot-lbs. The transmission bell housing bolts need to be tightened to 25 foot-lbs. The harmonic balancer retaining bolt should be tightened to 85 foot-lbs. The bolt threads for the flex plate for automatic transmission-equipped vehicles or the flywheel for standard shift vehicles need to be coated with a thread locker and tightened to 60 foot-lbs.
The oil pan retaining bolts on the underside of the engine block should be tightened to 12 foot-lbs. The bolts holding the timing cover to the front of the engine should be tightened to six foot-lbs. while the valve cover bolts should be tightened only to three foot-lbs.
