Hypereutectic pistons are finished with Grafal anti-friction coating and swing on powdered-metal rods. The crank is a nodular-iron piece with rolled fillets and is capable of handling much more if the wick is turned up. Its camshaft is also a bit hotter than the production LM7 and raises the maximum engine speed to 6,000 rpm. The cylinder heads are the familiar cathedral-port design. Cast in aluminum, they feature 1.89-inch intake and 1.55-inch exhaust valves, a 61cc chamber, and flow 226 cfm at 0.600-inch lift. This makes for a flexible and responsive street engine.
This version of the 5.3L is set up for compatibility with either carburetion or EFI. The recommended manifold for this application is the PN 88958675 four-barrel intake, a cast-aluminum open-plenum intake manifold that accepts a 4150-style square-bore carburetor. It allows the installation of a four-barrel carburetor on any LS series engine with cathedral ports.
A 770-cfm Holley four-barrel carburetor with vacuum-operated secondaries and electric choke is recommended for the LS327/327 engine. GM Performance Parts has a 770-cfm Holley carburetor (PN 19170093) with vacuum secondaries. The engine consists of all new componentry and carries a 24-month/50,000-mile warranty.
Dr. Jamie Meyer, product integration manager at GM Performance Parts, slipped us this little tidbit of information: There will soon be an E-Rod version of this engine coming to market.
What's an E-Rod? We'll let the good doctor explain. "This engine will be out about the time that your readers get this magazine," he added. "It is a very exciting product, because our engineers have harnessed all of the emissions-control systems, packaged them with the ultra-reliable 5.3L GM V-8, and deliver it as one complete system that is emissions-compliant in California and all states that follow California ARB regulations. The 5.3L offers incredible value: 325 hp and 345 lb-ft of torque. We're going to try to bring this entire package (brand-new 5.3L engine, manifolds, cats, LS controller, wiring harness, custom GMPP calibration, and installation manual) out to the market for under $5,000!"
This is exciting news for anyone looking for smog-legal power in an emission-control-equipped car or truck. Now your Third-Gen Trans Am, G-body '78-'87 Grand Prix, or even a muscle-era machine can be repowered legally-even in California.
Engine Buildup Worksheet
List Price: $4,030
Street Price: $3,175-$3,600
| Engine Displacement: |
328 ci |
| Horsepower: |
327 at 5,500 rpm |
| Torque: |
347 lb-ft at 4,600 |
| Bore/Stroke: |
3.78 x 3.66 |
| Block/Crank Combo: |
High-nickel-content cast-iron block, |
| six-bolt, cross-bolted mains, nodular-iron crankshaft |
| Bore/Stroke Ratio: |
1.032:1 |
| Rod/Stroke Ratio: |
1.66:1 |