At the Miami International Boat Show, gamesmanship among boat and engine manufacturers is par for the course—and it’s really fun to watch. The 2012 event, which happened in February as it always does, was no exception.

What do I mean by gamesmanship and what the heck—in this case—am I talking about?

At precisely 10:05 a.m. on Thursday, Feb. 16, Mercury Racing pulled the sheet off of its new 565 engine, a naturally aspirated 565-hp “tweener” product, separated by the 525 EFI and the 600 SCI offering. Just minutes later and one Miami Convention Center row away, Ilmor Marine unveiled its 570-hp V-8 LS-platform naturally aspirated engine dubbed the MV8 570.

Mercury Racing's 565 comes standard with digital throttle and shift.

“That’s just the power the engine made,” said Jessica Gamarra, the director of sales and marketing for Ilmor Marine, with a wry smile.

As I said, gamesmanship is a given at the Miami International Boat Show, and in this case the gamesmanship is fierce. With products from 525 hp to 1,350 hp Mercury Racing is the unquestioned leader in high-performance marine engines and outsells Ilmor Marine by a large margin. Yet Ilmor Marine, a Penske company, has made inroads to the Mercury Racing-dominated go-fast engine world like no other player ever has. And for that reason, Ilmor has replaced Sterling Performance Engines as Mercury Racing’s archrival.

But to chalk up the primary difference between the two competing engines as that of just five horsepower would be overly simplistic. Here’s a closer look at each powerplant.

Mercury Racing 565

The new 565 is based on the same block as the Fond Du Lac, Wis., company’s stalwart and top-selling 525 engine, but stroked to create an additional 31 cubic inches of displacement—533 cubic inches total. That accounts for the 565’s power output above its 525 sibling. While both engines come standard with Mercury Marine’s SmartCraft engine management and information system, the 565 also has digital throttle and shift, which makes for smooth operation.

The closed-cooled engine runs on 89-octane fuel. Features include redesigned cylinder heads, multiport fuel injection, and twin electronic throttle bodies.

The 565 is equipped with the same Propulsion Control Module microprocessor as the more powerful quad overhead cam turbocharged 1100- and 1350-hp Mercury Racing engines. In addition to providing digital throttle control, the PCM-enabled system also features one-touch Smart Start, automatic throttle synchronization, and “shadow mode” for triple engine applications in which two throttle levers can operate up to three engines.

A second microprocessor—unique to the 565—called the Transmission Control Module, provides smooth, "Zero Effort Digital" shifting of the mechanical Bravo One XR drive train.

Drive options for the 565 include the standard Bravo One XR and Bravo One XR Sport with 1.35:1 or 1.5:1 gear ratios. Mercury Racing’s Integrated Transom system is also available.

On the aesthetic side, the 565 comes standard with a carbon fiber top, a styling cue taken from the 1100 and 1350 engines, which also protects the engine’s electronics. The engine is available in 11 colors, including standard “Raven” black and Mercury Racing metallic blue.

The 565 comes with a Bravo One XR drive and a one-year limited warranty for recreational boating.

Ilmor Marine MV8 570

Ilmor's MV8 570 engine actually began its life, so to speak, in another application. The Plymouth, Mich., company developed a catalyzed, 522-hp version of it for MasterCraft, and is currently building 300 units a year for the popular towboat company.

Ilmor’s MV8 570 small-block engines features LS design architecture.

Gone from the high-performance, higher-output version of the engine are the catalytic converters. But from the high-performance boat perspective, the hottest feature of the MV8 57 is that it employs LS design architecture, which is why the 7.4-litre, 454-cubic-inch engine is considered a small block. Before the LS platform was released, engines with greater displacement than 350 cubic inches generally were categorized as being in the big-block family.

Among other things, the engine’s LS architecture translates to a more compact package. The closed-cooled MV8 570 is 2 inches shorter and narrower than Ilmor 8.2-liter, 502-cubic-inch engines. What’s more, it's 300 pounds lighter than Mercury Racing 565.

The MV8 570 runs on 87-octane fuel and features a dual-equal hydraulic phaser that adjusts cam timing for intake and exhaust valves. According to Ilmor, the engine is hand-built to the same exacting specifications as the company’s V-10 engines, which make up to 725 hp.

Unlike the Mercury Racing 565, which as noted above comes with a Mercury Bravo One XR drive, Ilmor’s MV8 570 does not come with an integrated stern drive package. (Ilmor MV10 series engines up to 725 hp come with the company’s Indy drive.) Paul Ray, the president of Ilmor Marine, has said that the company eventually will develop a drive for the 570, but until then buyers will have to choose aftermarket drives from Teague Custom Marine, IMCO, and others. The MV8 570 also does not come with digital throttle and shift, and won’t until Ilmor releases its own drive.

Both the Mercury Racing 565 and Ilmor MV8 570 are intriguing, and both come from companies with serious engineering credentials and reputations for building high-quality products. Each has its own attributes.

So which engine is the better call? With respect and admiration for the products and people of both companies, that’s one game I just won’t play. Better—and more fun—to watch and see.

Matt Trulio