Don't Call 'Em Small

At what point is a small-block no longer small? That's hard to say, but we have to admit that we have a tendency to giggle every time we hear World Products' Motown crate engines referred to as "small-blocks." Oh sure, the external dimensions may be the same as those compact Chevy V-8s that began life long ago with 265-inch displacements, but with cubic inch figures of 415, 427, and now the latest offering of 443, these engines are anything but small!

Building small-block engines with big block displacements is nothing new--after all, 383-inch stroker engines have been around for years, and Chevrolet even pushed the mouse motor to 400 cubes in production form. But it is news when you start building streetable, pump-gas crate engines--not exotic race pieces--to such mammoth displacement and performance levels. Of course, that's just what you'd expect from a company like World Products.

For the uninitiated, World Products began making a name for itself years ago with its successful line of Merlin blocks and heads-- new big-block castings that made it easier to build giant engines. Recently, the company's Motown line of small-block castings has made similar gains, putting stroker-ready engine parts into enthusiasts' hands at the right price. World's Merlin and Motown crate-engine programs, run by performance guru and World owner Bill Mitchell, put the versatile castings together with name-brand parts to create big-inch power for the masses.

That's where this engine comes in. The Motown series of crate engines began with the Motown 415, an engine that's selling well because of its big displacement, good value (priced between $7,500 and $8,000), and significant power (about 465 hp and 490 lb-ft with iron heads, and 485 hp and 505 lb-ft with aluminum heads). It's better-selling cousin, the Motown 427, costs between $1,500 and $2,000 more and is good for 505 hp/520 lb-ft with iron heads and 530 hp/540 lb-ft with aluminum. So, since the block will hold up to just about any tool the machine shop can throw at it (more on that in a minute), why not go bigger? That's just what World did, upping the ante to an astounding 443 cubic inches! At some point, we can't think of these as small-blocks--all the performance guidelines have changed.

STURDY STUFFWorld's big-inch small-blocks are made possible by fresh engineering from the get-go. The Motown block and heads are cast by the company to beefier specs than standard GM parts. The four-bolt Motown block, for example, has 1-inch thicker front and rear bulkheads for added strength. There's also more iron around the cylinders, allowing for expanded coolant passages. All that extra metal allows for larger bores--the Motown 415 has a 4.125-inch bore while the 443 has 4.200-inch cylinders, and there's still plenty of material left.

Nodular iron main caps are cinched down with half-inch bolts and alignment dowels. That may seem surprising, as a lot of high-end engines make use of splayed billet caps. "Nodular iron caps expand and contract better with the heat of the engine block," Mitchell explains. "This is better for the overall life of the bearings." Besides, anything more exotic really isn't necessary at this power level, although World will be happy to sell you billet caps if you're building a blown engine or something more serious.

The crankshaft itself has a long 4.000-inch stroke (3.875-inch on the 415) and is internally balanced, which means the counterweights carry any necessary balancing work. Externally balanced cranks typically wear weights attached to the front and/or rear of the crankshaft. The internally balanced crank is likely to last longer and make the engine run smoother.

Big bores and long strokes are great, but the numbers game doesn't end with the short-block. "Cubic inches won't [make horsepower] alone," Mitchell says. "You've got to follow through with cylinder head flow." Enter the Motown 220 cylinder heads, which are also of World Products' own design and casting specifications. They feature large 220cc intake runners (compared to a stock-type head's 170cc volume) for lots of flow to the 64 cc or 72 cc "fast burn" combustion chambers. The bean-shaped chambers promote quicker light-off of the air/fuel mixture, as well as more complete combustion. In keeping with the "big holes for big power" theory, the valves measure 2.125-inches on the intake side (2.080-inches for the 415 engine) and 1.6-inches on the exhaust. They're typically actuated by a Crane hydraulic cam, though a solid roller valvetrain is also available.

THAT'S NOT ALL...The balance of the Motown engines read like a who's who of the performance aftermarket: Manley, Fel-Pro, ARP, Speed-Pro, and so on. Forged aluminum pistons are standard issue, and compression ratios are intentionally kept low (typically around 9:1 with iron heads and 10:1 with aluminum) so that drivers can fill up on pump gas--even 87-octane stuff. The 443 has been tested with both an 1150-cfm Dominator carb and a Holley Commander EFI, while the 415 comes standard with a modified Holley 870-cfm four barrel. Completed engines include plugs, wires, an HEI distributor, and a harmonic balancer. Because of variables in applications, water pumps and flywheels are not included.

World doesn't stop with top-notch parts and professional assembly, though. A World technician tests every engine on a dynamometer. "We don't just make sure it runs and makes our horsepower numbers," Mitchell says. "It's tuned and rechecked so it performs optimally." Unfortunately, regulations prohibit shipping the engines with oil in them. World fills each new engine with fresh oil, only to drain it after the dyno session. "It's kind of a shame to go through all that oil so quickly, but it's the best way to test the engine and still ship it without hassle," Mitchell says. "After the dyno test we drain the oil, spin on a new filter and crate up the engine."

As of this writing, there were only a couple of examples of the Motown 443 built, but regular production should have started by the time you read this. (They've been building Motown 415s for more than a year now.) Based on testing, a 443 with iron heads and a hydraulic cam will make about 550 hp and 550 lb-ft. of torque and set you back about $10,000. An all-out version with aluminum heads, roller valvetrain, Jesel belt drive and other goodies will produce 595 hp and 576 lb-ft, and cost around $15,000. Folks, that's serious big-block power in a package that weighs in at 535 pounds, or about 125 pounds less than a typical big-block Chevy! Even the Motown 415--conservatively rated at 465 hp and 490 lb-ft--will outshine most Rat motors. And keep in mind that these aren't race engines running on the ragged edge -- they're street engines that idle well and offer day-to-day reliability while still delivering smooth, flat horsepower and torque bands.

Yeah, we know that Motowns aren't the least expensive engines out there, but you'd be hard pressed to find more power in a small-block crate engine. You'd probably have to source a custom-built powerplant (in which case, Motown blocks and heads are available separately). And though custom-built engines fill a niche for some, there's piece of mind that goes with a tried, tested, and warranted (2 years or 24,000 miles) combination such as this. Add it up, and you'll see that Motown engines offer a big bang for your classic truck buck.