For years, the 360-cube Sprint Cars have been considered by many to be the inferior little brother to the big 410 cubic-inch-powered cars sanctioned by the World of Outlaws and other professional touring series. But, thanks to modern block technology, like the World Products Motown III, the 360s have come a long way and are now pushing over 750 horsepower (and $65 grand!).

The competition is tighter than ever before, and racers and fans alike are drawn to the packed fields and great racing. So, we’re taking a closer look at these unique race engines with the help of Ostrich Racing Engines, who pulls back the curtains on how these V8 monsters, built around the ASCS (American Sprint Car Series) rulebook, are built with precision, persistence, and a whole lot of know-how from decades in the trenches.

360 Sprint Car engines undergo extreme stress. They have to be able to go an entire racing season between rebuilds, pumping out over 750 horsepower and 8,500 rpm lap after lap without a single hiccup. So, premium components are critical. Ostrich Racing Engines has found World Products’ new Motown III block has the right mix of strength and smart design right where they need it. You can see the machining marks in the valley where Ostrich Racing Engines has put the cast-iron block (mandated by the rules) through a lightening program.

Factory Roots to Global Reach

Ostrich Racing Engines is one of the old-guard when it comes to Sprint Car racing. The business began life under Gary Ostrich as one of just nine factory shops in the 1970s. Current owner Lee Nelson eventually bought the business and decided to keep the name—a nod to its legacy and a smart play to keep old customers close. Today, Ostrich engines built in the heart of Iowa are roaring in Australia, Canada, and all over the American dirt scene. “We’ve won the 360 Nationals a few times,” Nelson says matter-of-factly. “Had multiple 410s qualify for Knoxville. Track championships. We’ve been around.”

Built to Last Through the Chaos of Dirt Racing

Sprint car engines take a beating. That’s especially true in the 360 classes in all of the sanctioning bodies, where the engines are pushed to the absolute limits to make power despite the limited cubic inches. To withstand the punishment, Nelson and the team recently switched to World Products’ updated Motown III block. “With the changes they made, that Motown block became a really nice option for us,” Nelson says. “A strong deck is critical, so they beefed that up, moved some metal around — and it turned out to be a really nice block.”

Ostrich cuts down the decks as much as possible to move the engine’s center of gravity lower in the chassis. The Motown block’s thick decks allow them to do this with plenty of meat left to prevent warping.

Weight is always a consideration, but durability took precedence. “We lightened it where we could,” Nelson explains. “But mainly, we just wanted strength in the right places — thicker mains, beefier decks. Even when we short-deck the Motown III block to move the center of gravity lower, there’s still plenty of meat there, so they aren’t warping on us.”
Inside the Beast: The 360 Sprint Combo

The engine has to be able to go a full season between rebuilds, so quality components are critical everywhere. For the rotating assembly, the key is finding the optimum mix between light weight and strength, so the crew at Ostrich went with a Callies crank, Carrillo rods, and CP pistons. To get to 360 cubic inches, the bore will be 4.135 inches with a 3.335-inch stroke. The short stroke helps limit piston speed, but it also means the bore can be increased, which helps move the cylinder walls away from the valves for better breathing.

The stock cam retainer plate does have to be modified to accept the gear drive that will be going on later. Also, the cam tunnel of the Motown III block has been machined to accept roller bearings and a thick 50 mm camshaft that’s more resistant to twist.

On top, a set of spec heads from Brodix are mandatory, but much of the rest of the valvetrain is open. Aluminum shaft-mount rocker arms from Jesel keep things breathing. They activate titanium valves from Del West and SRI valve springs — springs that, thanks to Spintron testing, deliver serious control with only 200 pounds on the seat. “We were running 240 to 250 pounds before and losing control around 8,400 to 8,500 rpm,” Nelson says. “These new springs let us rev to 9,800 rpm without losing control of the valves.”

One of the great features of Motown small-blocks is priority main oiling. To improve main bearing life even more, Ostrich drills out the galleries to 5/16 of an inch. Also, notice the roller cam bearings that have been installed to reduce power-robbing friction inside the engine and also help keep oil temps down.

The cam is a custom bump stick from Erson. This is no shelf-stock cam; Nelson has custom intake and exhaust lobes developed with lots of Spintron testing and years of racing experience. There’s no way he’s giving up all the specifics, but he was willing to give us a peek: “It’s 266 at .050, around .750 lift,” he says. That’s matched to a gear drive from Shaver Wesmar up front and an old-school Sprint Car-style magneto from MSD for ignition.

Fuel is handled by a Kinsler injection system, with oil handled by a Dan Olson pan and Saldana remote tank. Hoses and fittings? Brown and Miller, of course.

Weight is the enemy in Sprint Car racing. A Callies Ultra Lite crankshaft has scalloped counterweights and a starred flange to take out every ounce possible for extreme acceleration.

Methanol-Powered Madness

Like almost all Sprint Car engines, this one runs on methanol, a fuel that comes with its own quirks. It burns cooler, which helps engine longevity and cuts the chances of detonation, but with a stoichiometric ratio of just 6.47:1, it also demands double the fuel load compared to gasoline. That means bigger injectors, more aggressive timing, and a tuning strategy all its own.

“Methanol likes compression,” Nelson explains. “We’re around 15:1. With the shorter stroke of a 360, you’ve got to pack a lot of piston dome into a small head.” That means custom pistons with careful attention to detonation resistance. “We hand deburr the pistons wherever we can to eliminate hot spots,” he adds.

The CP Pistons slugs feature big domes and even stick out of the block .005 inch at TDC to maximize compression. Ostrich Racing Engines hand-blends every edge to eliminate hot spots and reduce the chance of detonation.

Airflow Isn’t Just About Size

While the rules say “spec heads,” that’s a loosely defined term in the world of 360 Sprint Car racing. “You have to run a specific cylinder head, and you can’t mess with the area of the port that’s got ‘spec’ written on it,” Nelson says. “But you can pretty much do what you want inside.” In other words, it’s a wide-open playground for smart cylinder head porters and flow bench junkies.

Still, Nelson isn’t chasing the biggest valve he can wedge in there. “We’re not running 2.150s or anything like that. We’re at 2.100-inch valves, maybe a little more. It’s not just about raw size. Go too big and you start shrouding the valve, anyway.”

Even the stem diameter is a balancing act. “We’ve tried 7mm stems,” he says. “But we’re still mostly running 5/16-inch. Methanol helps keep things cool, and we haven’t seen enough gain to switch.”

A Shaver Wesmar camshaft gear drive is very durable and ensures the cam timing stays spot on throughout a night of racing.

Power, Torque, and the Real Secret Sauce

On the dyno, this Motown III-based motor makes 766 horsepower and 608 lb-ft of torque — numbers that would’ve seemed insane for a 360 just a few years ago. And it holds that power over a wide range, with a flat curve from 7,700 to 8,400 rpm. And that means better acceleration all the way down the straights. “These engines used to be peaky,” Nelson admits. “Now, with better cams and less friction, we’re getting really flat curves.”

So what’s the secret? It’s not some one-time breakthrough. It’s the grind. “Every engine that leaves here is R&D,” Nelson says. “We’re always learning. Friction reduction, valvetrain control, airflow — every build teaches us something new.”

The rockers are aluminum units from Jesel and shaft-mounted for improved high-RPM valve control.

Trackside Tuning: Still a Critical Part of the Process

Despite all the tools, dyno sheets, and simulation software, Nelson insists that one of his most valuable resources is still the race track. “Being at the track tells you what the dyno doesn’t,” he says. “Drivers and crews know what it’s doing out there. That feedback is critical.”

And it’s not just about max power — it’s about making that power live. “You can run 20 to 25 nights on a 360,” he says. “Compare that to a 410, where you might get 12–15 nights before it needs attention.”

In this photo, you can see the iconic Kinsler individual runner intakes with mechanical fuel injection. This is a dry sump oiling system, and, although it is a bit tough to see, the multi-stage oil pump is driven off the cam gear and sticks out of the front of the engine. The external oil tank is attached to the front of the engine and makes it easier for teams to do an engine swap between heats if things go sideways.

Beyond the Numbers

Of course, it takes more than power and longevity to build a winning motor. It takes a team that sweats the details. From valve spring selection to how much dome to run on a piston, everything’s chosen with intention. Nelson doesn’t throw parts at a problem — he experiments, observes, and evolves.

And that’s the real secret when it comes to regularly finding victory lane in the most competitive forms of racing. These engines aren’t just machines — they’re proof of what happens when tradition meets innovation, and when one builder refuses to stop learning.

You can see it is a very tight fit inside the confines of the Sprint Car chassis.