The ZZ6 350 is built with a cast-iron block with four-bolt mains, along with a forged steel crankshaft, an aggressive hydraulic roller camshaft and durable, high-silicon pistons. All-new, motorsports-inspired valve covers distinguish this new crate motor at a glance, too – along with Chevy "Bowtie" insignias in the ends of the cylinder heads that let everyone know you've got the latest GM Performance hardware under the hood.

This Turn-Key engine package includes the distributor, and balancer installed. The carburetor, starter, fuel pump, air conditioning pump, alternator, single belt front-end accessory drive kit and more are also included. Chevrolet Performance also offers the ZZ6 350 base engine at a lower price, allowing you to finish your new engine your way.

ZZ6 BASE TECH SPECS:

• Engine Type: Chevy Small-Block V-8
• Displacement: 350 ci
• Bore x Stroke: 4.000 in. x 3.480 in.
• Block: Cast-iron with four-bolt main caps
• Crankshaft: Forged steel, 1-piece rear main seal
• Connecting Rods: Forged powder metal
• Pistons: Hypereutectic aluminum
• Camshaft Type: Hydraulic roller (steel)
• Camshaft Lift: .474 in. intake / .510 in. exhaust
• Camshaft Duration (@.050 in.): 208-degree intake / 221-degree exhaust
• Cylinder Heads: 'Fast Burn' aluminum, 62cc combustion chambers
• Valve Size: 2.000 in. intake / 1.550 in. exhaust
• Compression Ratio: 9.72:1
• Rocker Arms: Aluminum roller style
• Rocker Arm Ratio: 1.5:1
• Distributor: HEI type
• Intake Manifold: Single plane aluminum
• Carburetor: Holley 770 cfm
• Water Pump: Cast-iron, long-style
• Recommended Fuel: Premium pump
• Ignition Timing: 36-degrees Total @ 4000 rpm
• Maximum Recommended RPM: 5800
• Flexplate: 12.750 in. diameter, 153-tooth
• Balanced: External

Installation Notes:

• Comes with a 12.750 in. externally balanced 153-tooth automatic transmission flexplate. Change to an externally balanced flywheel for manual transmission applications.
• Requires fuel line from the fuel pump to carburetor
• Designed for pre-1976 street vehicles or any off-road vehicle.
• Some assembly and minor engine tuning required
• Not intended for marine application
• Distributor with melanized steel gear MUST be used with long-blocks and Partial engines with steel camshafts, or engine damage will occur.

Engine Break-In Procedure

Use conventional or break-in oil (non-synthetic) for the first oil change, be sure to check the oil level in the engine and prime the oil system with an engine priming tool. 

Engines with flat tappet hydraulic cams only - Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. This is critical to break in the camshaft.

Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM.  Run five or six medium-throttle accelerations to about 3000 RPM (40 to 50 MPH), then letting off in gear and coasting back down to 20 MPH. Run a couple of hard throttle accelerations up to about 5000 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.

Let the engine cool and change the oil and filter using conventional (non-synthetic) oil and check the coolant level, top off if necessary. Drive the next 500 miles normally, without high RPM's (below 5000 RPM), hard use, or extended periods of high loading.  Change the oil and oil filter again using conventional (non-synthetic) oil.  Keep an eye on oil level during the first thousand or so miles.

It would be suitable to use synthetic motor oil after the second recommended oil change and mileage accumulation.