350-inch Small-Block Chevrolet- Car Craft Magazine

Just the facts, ma’am.
The 1986-and-later engines use a one-piece rear-main-seal crank (left) with a downsized 3.00-inch-diameter flywheel flange bolt pattern. The earlier two-piece seal crank (right) has a 3.58-inch-diameter pattern and extra counterweight.
The 1986-and-later engines use a one-piece rear-main-seal crank (left) with a downsized 3.

Selected high-perf and truck applications use four-bolt main caps on main-bearing journals 2, 3, and 4. This is a late-block with the one-piece rear main seal.
Selected high-perf and truck applications use four-bolt main caps on main-bearing journals
Most 1987-and-later 350s have factory hydraulic roller tappets. A stamped-steel guide retainer bolted to the lifter valley aligns the factory-type hydraulic tappets on the cam lobes. Some 1986 blocks have the extra bosses for the retainer mounting bolts, but they aren’t always tapped.
Most 1987-and-later 350s have factory hydraulic roller tappets. A stamped-steel guide reta
With its geardriven water pump; front-mounted, optically triggered distributor; and reverse-flowing cooling system, the LT1 has only limited part interchange with earlier small-blocks.
With its geardriven water pump; front-mounted, optically triggered distributor; and revers

The 1978- and-later lightweight castings (top, compared to traditional casting, bottom) should be avoided on a serious performance engine. Identify lightweight castings by the scallops between the lower row of head bolt holes (regular castings are straight in this area).
The 1978- and-later lightweight castings (top, compared to traditional casting, bottom) sh
Late-model heads factory-equipped with 2.02-/ 1.60-inch valves come with screw-in rocker-arm studs and pushrod guideplates. Although a late 882 head is shown here, this feature first appeared on the 1970 414, Z28/LT-1 casting.
Late-model heads factory-equipped with 2.02-/ 1.60-inch valves come with screw-in rocker-a
A new rocker-cover design with four central retaining bolts is used on 1987-and-later engines. To reduce leakage, it features raised rails to move the gasket above the oil drain-back level. The new cover’s internal flanges also distribute the clamping load more evenly.
A new rocker-cover design with four central retaining bolts is used on 1987-and-later engi

Introduced in 1967, the 350 pioneered larger 2.45-inch main journals and 2.10-inch rod journals, beefier 3/8-inch rod bolts, four-bolt main-bearing caps (for selected applications), and a reinforced cylinder block. As this is written, the 350 is still in production more than 30 years later, and there have been more 350s built than any other small-block Chevy. It has survived the dismal '70s to emerge stronger than ever in its current GEN II (LT1/LT4) and Vortec pickup-truck configurations.

If you're building up a small-block today, chances are the core will be a 350. But sheer numbers alone don't entirely account for the engine's popularity. In the real world, the 350's 3.48-inch stroke and 4.00-inch bore combine to produce a good compromise between midrange torque and top-end power. This makes the 350 an engine for all seasons, whether at home in a tow vehicle or as the basis for a stout drag race or oval-track motor. Since the engine is still in production and there are millions of units in service, parts pricing and availability are no problem. Most of today's aftermarket parts, such as cams, intakes, and exhaust headers, are optimized for the 350-inch displacement size. If the 350 is deficient in any area, it is connecting-rod length. The 5.7-inch rods common to most other small-blocks yield a 1.64:1 rod/stroke ratio (R/S, or rod center-to-center length divided by crankshaft stroke). Many professional engine builders install longer aftermarket 6.0-inch rods, which increases R/S to a more favorable 1.72:1. A budget-oriented approach would be the 5.94-inch rod from a '94-'96 4.3L V-8 Caprice, which yields a 1.71:1 ratio. Either way, custom pistons are required.