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Small-Block Lite

World Products' all-aluminum Motown small-block is the "low carb" alternative

Just as your doctor has told you excess weight isn't good, so it goes for your Camaro. Never the most featherweight of muscle cars, Chevy's nose-heavy pony car benefits greatly with every shed pound-especially up front.

A fiberglass hood will shave some weight, as will a set of aluminum heads. But if you really want to lighten your Camaro's front end, World Products' new Motown "Lite" aluminum small-block crate engine might just be the ultimate weight-loss plan.

Although World Products has been offering Motown engine assemblies for a couple of years now, it only recently started building them with their all-new aluminum block. Compared to the standard iron block, the alloy version weighs only about half as much.

"With this block and aluminum heads, you get an engine that weighs only about 435 pounds," says World's Bill Mitchell. "That won't even compress the front springs on some cars."

Like the iron version, the alloy Motown Lite is strategically beefy. The 357-T6-cast bare block (with main caps and cylinder liners installed) weighs just 100 pounds-an iron Motown block weighs about 195 pounds.

Besides its light-grey aluminum coloring, the most obvious deviations from the World Products' iron small-block or, for that matter, GM's own small-block Chevy, is the horizontal strengthening ribs along the cylinder banks. They add strength and are connected internally to serve as cross-feed oil galleries.

The extra meat in the block's casting is mostly on the inside, so all the Chevy small-block accessories, from intake manifolds to fuel pumps, bolt up as with a stock engine. The extra metal, however, allows World Products to slip in some thick cylinder liners and create Mitchell's signature big-displacement torque monsters. A 427ci displacement is the maximum with a 4.000-inch crank (the iron block can yield a 454 displacement).

One of the block's other unique features is a series of O-rings at the bottom of the cylinders. They help hold the liners in place and prevent oil from squeezing between the liners and block - then bane of many aluminum engines.

"When it gets up there, the oil acts like an insulator and prevents the aluminum from transferring heat," says Mitchell. "It also helps dislodge the liners."On top of this lightweight foundation, World Products bolts on its time-tested roster of power-building components - each selected to help move air efficiently through the voluminous passages. Motown 220 heads, named for their huge 220cc intake runners, have equally large 2.055/1.600 valves.

Straddling the heads is Motown intake manifold topped by an 870-cfm carb. Technically it's a single-plane intake, but a unique "spider" design allows the engine to make useable low-rpm power and torque. This was important as Mitchell sees this engine as much as a street performer as a race engine.

"It's a great street engine," says Mitchell. "It idles great and makes lots of power down low; you can cruise all night with this."

Much of the street friendliness of the big-carb motor is due to a special-grind camshaft from Crane that produces great idle quality and very good high-rpm power. Not surprisingly, Mitchell wouldn't divulge the cam's specs, but our experience with his crate engines has shown that they seem to strike a great balance of power and tractability.

World Products rounds out their engine assemblies with an HEI-style distributor, plugs, wires, deep sump oil pan, and SFI balancer and a great looking set of valve covers. As with most other crate engine packages, vehicle-specific items, like the water pump and headers, are left to buyer to source.

Each engine, however, is dyno tested before being crated and shipped.

So, what'll it do?

What is the all-aluminum 427-cid Motown small-block worth on the dyno? At our writing, Mitchell was still trying to determine an average on which to base his advertised claims, but here's what he told us:

"They've been making around 535 hp and 540 lb-ft of torque," he says. "They run right up to 6,300 rpm, too."

Mitchell says he's surprised because the aluminum engine is making as much and, in some instances, more power than comparable iron-block engines. "It's puzzling," he says. "Power should have probably dropped a little, due to the thermal differences between the iron and aluminum, but we got just the opposite. It was a pleasing surprise, to say the least."

Mitchell attributes the engine's stalwart performance to the extra-rigid aluminum block and its numerous strengthening features, which probably provide less flex in the reciprocating assembly. Regardless, the lightweight small-block makes power--tons of it.

If you're thinking all this performance wrapped in a lightweight package must come at price, you're right. The all-aluminum Motown is not an inexpensive option. It adds approximately $2,000 to the bottom line of the base price of a Motown crate engine, and the iron-block versions of the 427 start at around $8,995.

So, you're looking at package of about $11,000 to $12,000 when they've nailed the crate shut and maneuvered the forklift into position.

But, compared to some exotic race castings, World's aluminum block costs roughly half and were designed as much for street performance as competition.

"We learned a lot in the manufacture of other parts that really helped make this affordable," says Mitchell. "We wouldn't have done it if we were building just 100, or so, each year for sprint cars."

There's an undeniable "wow" factor, too, that plays an important role. You wouldn't want to paint this block - just let the aluminum color and external ribbing do the talking under the hood of a Pro-Touring '69 Camaro"I think it'll look awesome polished," says Mitchell.

Indeed, others have thought so, too. Since making the all-aluminum Motown engine available, it has quickly become one of the company's best sellers.

It's hard to argue with the benefits of lower weight. Your doctor will tell you that, and so will Bill Mitchell.

World Products 427-CID "Motown Lite"
CYLINDER CASEAluminum with steel sleeves, four-bolt mains
BORE x STROKE4.125x4.000 inches
CRANKSHAFT4340 forged steel
CONNECTING RODS4340 forged steel H-beam
PISTONSForged aluminum
CYLINDER HEADSAluminum with 220cc intake runner volume
VALVESStainless steel, 2.055 inches (int), 1.600 inches (exh)
VALVETRAINAluminum roller rocker arms, 4130 pushrods
TIMING SETDouble-row, true roller
INTAKE MANIFOLDSingle plane aluminum
CARBURETOR870-cfm four-barrel
IGNITIONHEI distributor, 8mm plug wires
HORSEPOWER535 (preliminary)
TORQUE (LB-FT)540 (preliminary)
RPM RANGE6,300 (preliminary)
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