Life is made up of simple equations--especially if your life revolves around cars. A '68 Camaro plus a 6-71 blower equals a hole in the hood. Nitrous plus school zone equals a suspended license. Our editor, Terry Cole, plus an early Chevy II for sale equals his family eating macaroni and cheese for a month. Simple stuff
For the folks at World Products, the equation goes like this: MoTown cylinder heads plus all-new MoTown engine block equals 475hp small-block crate motor.
"How could we not do it?" says World Products' President Bill Mitchell. "We've cast our own heads for a while, then we started recently with the blocks. Offering a complete engine was the logical thing to do."
Makes sense to us.
But rather than simply offer a lukewarm engine package for lukewarm cars, World Products comes out of the box with the MoTown 415. The name doesn't refer to the horsepower figure--it's the displacement of the all-new small-block. And since you're wondering, World rates the MoTown 415 at a conservative 475 horses and 525 lb-ft of torque. We know it's conservative, because we followed the assembly process and watched one of these crate monsters on World's dyno. It made more than 482 hp and more than 545 lb-ft of torque.
"We're seeing these numbers pretty consistently, within a few percent, so we may raise our quoted number," Mitchell says. "That 475 figure is a good one, though, so no matter who buys a motor and dynos it, he shouldn't be disappointed. In fact, he'll probably be very pleased with the better-than-expected performance."
With numbers that would otherwise indicate big-block power, the MoTown 415 obviously makes efficient use of its air passages. Four-inch bores and a 3.875-inch stroker crank deliver the cubes, while a free-breathing, fast-burn-style set of MoTown 220 heads (220cc intake runners) allow for plenty of hard-charging combustion.
The key to the engine's tremendous output is its ability to rev higher and sustain the power and torque bands at nearly 6,000 rpm. The block and heads were designed for such high-rpm antics, and when utilized together, it's a combination that pulls as hard and revs as smoothly as any small-block we've encountered.
World's MoTown block and heads are cast by the company to beefier specs than standard, GM-cast parts. The four-bolt MoTown block, for example, has 1-inch-thicker front and rear bulkheads for added strength. There's more iron around the cylinders, too, than a stock block. This allows for expanded coolant passages and head bolts that don't go into water.
Nodular iron main caps are cinched down with half-inch bolts and alignment dowels, while the crankshaft itself 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.
You may be surprised to learn that this sturdy block doesn't make use of splayed or billet caps.
"Nodular iron caps expand and contract better with the heat of the engine block," says Mitchell. "This is better for the overall life of the bearings."
The MoTown 220 cylinder heads, too, are of World Products' own design and casting specifications. They feature 220cc intake runners, compared to a stock-type head's 170cc volume, for lots of flow to the 72cc "fast-burn" combustion chambers. The bean-shaped chambers promote quicker light-off of the air/fuel mixture and a more complete combustion, too.
In keeping with the "big holes" for producing lots of power, the valves measure 2.055 inches on the intake side and 1.600 inches on the exhaust. They're actuated by a Crane hydraulic profile cam specific to this engine combination.
The old adage that an internal combustion engine is simply an air pump--the more air pumped in and out, the more power it makes--is a concept Bill Mitchell adheres to with a mathematical fanaticism.
"The cubic inches won't [make horsepower] alone," he says. "You've got to follow through with cylinder head flow. Remember: Horsepower is the product of torque divided by 5250 times rpm. A high-flow cylinder head is going to give you more rpm and, consequently, more power."
Air enters the engine through a modified Holley 750. Mated to a tweaked Holley 850 base, the carb flows 870 cfm into a street-friendly, dual-plane manifold. So that drivers can fill up on 87-octane, if necessary, the MoTown engine has a nominal compression ratio of 9.0:1. The pistons themselves are forged aluminum pieces.
The remainder of the engine's components read like a who's who of the performance aftermarket: Manley, ARP, Wiseco, Speed-Pro, etc. The completed assembly includes plugs, wires, an HEI distributor and a harmonic balancer. Because of so many variables in application, the few items not included with the MoTown crate motor are the water pump and flywheel.
After each engine is assembled, a technician tests it on a dynamometer. "We don't just make sure it runs and makes our horsepower numbers," Mitchell says. "It's tuned and rechecked so that it performs optimally."
Unfortunately, regulations prohibit shipping the engines with oil in them. World Products fills each new engine with fresh oil, only to drain it after the dyno test 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 any hassle," Mitchell says. "After the dyno test, we drain the oil, spin on a new, dry oil filter and crate up the engine."
SUPER CHEVY's visit to World Products' assembly and test facility included witnessing the dyno process from beginning to end. The test engine delivered smooth and flat horsepower and torque bands. The precision wail of the motor as it spun past 6,000 rpm was bettered only by the final power tallies: 482.4 hp and 545 lb-ft of torque.
All that power from a 9:0:1, 87-octane small-block is a great achievement. The 415 isn't the least expensive crate motor, 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 engine. And though custom-built engines fill a niche for some, there's peace of mind that goes with a tried and continually tested combination such as this one. We think the MoTown 415 is a terrific value for both race and street cars.
We plan to explore the greater possibilities of the MoTown 415 further. You'll have to come back to future issues to see what develops, but we'll leave you with this one-word hint: boost.