1966 396 Engine Factory Specifications

by Paul Novak
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classic image by Joshua Peterson from Fotolia.com

Produced from 1965 until 1969, the Chevy 396 engine began production as a full-service engine intended for use in a variety of Chevrolet vehicles. The 396 was based on a new block design that was later modified to increase displacement and create other legendary GM engines, including the 409 and 454. The 396 saw use in models such as the Chevelle SS, Nova SS and Camaro SS.

396 Basics

The Chevrolet 396 was introduced in 1965 and was based in what was known as the Mark IV block that later became the basis for larger displacement engines. The 396 engine is based on a 90-degree V8 design that uses a camshaft in the center of the block. The cylinder heads have two valves per cylinder mounted at unusual angles for a canted valve design to improve airflow. The valve train uses independently mounted rocker arms and push rods actuated by hydraulic lifters that ride directly on the lobes of the camshaft. Production of the 396 ended in 1969. Some later engines were advertised as 396s but were actually 402s.


The 396 crankshaft is either a cast or forged unit that is Tufftrided to improve durability. The crank is designed for use with a two-piece rear main seal. The 396 crank had a stroke of 3.76 inches. The main journals were 2.7482 to 2.7492 inches. The rear main journal diameters are 2.7478 to 2.7488 inches. The rod journal diameters are 2.1988 to 2.1998 inches. The crank in the 396 is secured into the block with either two- or four-bolt main caps, depending on the engine's intended application. The 396s intended for high-performance applications had the forged cranks and four-bolt main caps for added durability.


The Chevrolet 396 has a stroke of 3.76 inches and a bore of 4.094 inches. This bore and stroke combination in conjunction with different pistons and cylinders heads produced compression ratios for the 396 ranging from 9.0 to 11.00, again depending on the engine's intended applications. Base 396s intended for utilitarian applications tended to have lower compression ratios while performance versions of the 396 had compression ratios of 10.00 or higher.


The ignition system used on 396s is a points type unit that utilizes a camshaft driven distributor driven by a gear connecting it to the camshaft. The firing order for the 396 is 18436572, and the distributor rotates clockwise.


The 396 holds five quarts of oil, including the oil filter. The oil filter is a conventional spin-on type with a metal body and paper filter element. The oil pump is internally mounted and uses a pickup tube with a screened sump to pull oil from the bottom of the oil pan.


The 396 engine block and cylinder heads are iron. Various 396 applications used either cast iron cranks or forged steel cranks, depending upon their intended use as either a base engine or in a performance model. Intake manifolds are constructed of either cast iron or aluminum, with aluminum being used for some performance applications.


The 396 was offered in several configurations and produced different horsepower and torque ratings, depending on its intended application. The 396 with a 10.25 compression ratio produced 325 horsepower at 4,800 rpm and 410 ft. lbs. of torque at 3,200 rpm. The Z16 performance 396 with a 11.00 compression ratio produced 375 horsepower at 6,500 rpm and 420 ft. lbs. of torque at 3,600 rpm. The 396 with a 11.00 compression ratio produced 360 horsepower at 5,200 rpm and 420 ft. lbs. of torque at 3,600 rpm.

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