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ZZ4
STREET & RACE PERFORMANCE

GM Part# 24502609

Imagine an aluminum head small block that makes 355 horsepower. What if it had a street roller camshaft, 4-bolt main block, undercut rolled fillet crankshaft, high silicon pistons and strong PM connecting rods ? We imagined it, and then engineered, developed, tested and built it. The ZZ4 is the evolution of our popular ZZ series of small blocks that power thousands of street rods, hot street cars, circle track racers and drag racers. With over 400 Ft-Lbs of torque, the ZZ4 is the best way to put an aluminum head, roller cam, high performance small block between your favorite fenders.

The aluminum angle plug cylinder heads have screw in rocker studs, 1.94" intake and 1.50" exhaust valves and 58cc combustion chambers that yield a crisp and responsive 10 to 1 compression ratio. Also included are our lightweight valve spring retainers that weigh half as much as our previous design. The valve seats are radiused and we have included valve stem seals to help keep the oil where it belongs.

To compliment the cylinder head design, we've incorporated a steel roller tappet camshaft with .474" intake and .510" exhaust valve lift. The combination makes 355 horsepower at 5250 rpm and has that great sounding muscle car idle, with just enough lope to let people know this is no station wagon engine.

Also included with the ZZ4 is an HEI distributor with an ignition timing advance curve developed for performance, a dual plane aluminum intake manifold that accepts your spread bore or square bore carburetor, an 8" high-rpm harmonic balancer, 12.75" automatic trans flex plate and a cast iron water pump. It even has the spark plugs in it when it was test fired at the factory for quality control checks.

The ZZ4 is currently our most popular crate engine, and you can see why. With a long history of successes in circle track and drag racing as well as street rods and other performance applications, the ZZ4 may just be the bullet for your next project.

The ZZ4 is not intended for marine use, and should only be used in 1973 and earlier pre-emissions street vehicles or any year off road vehicle.

Technical Notes:   Carb, plug wires, starter, oil filter and oil filter adapter, and exhaust manifolds not included.

Displacement: 5.7 liters (350 cubic inches)

Horsepower: 355@5.250 rpm

Torque: 405 ft-lb @ 3500 rpm

Bore/Stroke: 4.00" x 3.48"

Compression Ratio: 10:1

Engine Block: 10105123 - Cast iron with four-bolt intermediate mains

Crankshaft: 12551485 - Nodular iron LT4 Corvette with rolled fillets

Connecting Rods: 10108688 - Forged powdered metal

Pistons: 10159436 - Cast aluminum with offset pins

Piston Rings: 14089025

Camshaft: 10185071 - Hydraulic roller tappet

Valve lift:
(Intake/Exhaust): .475"/.510"

Duration
(Intake/Exhaust): .208deg./.221deg @.050" tappet lift

Cylinder heads: 12556463 - Cast aluminum 58 cc

Valve Diameter
(Intake/Exhaust): 10168465 - 1.94" / 10168514 - 1.50"

Valve Spring: 12551483 - Single coil LT4 Chrome Silicon

Valve Lash: Zero

Rocker Arm Ratio: 10089648 - 1.5:1

Distributor: 11040607 - High energy ignition with centrifugal and vacuum advance

Spark Plug: FR5LS or AC Mr43LTS (.350"-.040" gap)

Spark Timing
10deg BTDC @650 rpm with vacuum advance disconnected and plugged
32° Total @ 4000 RPM

Max Engine Speed: 5800 rpm

Fuel Requirement: Premium unleaded 92 octane

Timing Chain: Single roller 1/2" pitch

Intake Manifold: 10185063 - Dual-plane high rise with dual pattern holly and q-jet