With outboards taking over the small and mid size sport boat game, it is refreshing to know that there are some incredible options for those of us who prefer sterndrive power. Big power sterndrives have some key advantages, power being one of them, but some boats just suit sterndrive power more. Plus, with a single 500 to 600 HP sterndrive, you’d have to run twin 300 outboards to get similar performance and twins can be cool but a big single is simpler and will have less drag. For pure top speed, having outboards way off the back can be beneficial, but a single big block is often lighter and brings the center of gravity forward for better rough water ability, and better overall handling. Let’s take a look at some of the most popular packages from Mercury Racing and Ilmor Marine, the 565 and 570. A close match in power and performance.

I would say both the 565 and 570 are the perfect engines for a mid size sport boat (25’-30’), whether it’s a brand new boat or you are repowering completely, these engines have the perfect blend of torque, reliability, cost and performance. I asked a couple manufacturers for their feedback on both these powerplants and in general, it’s a really close matchup. Here are the key differences.

Ilmor MV8 570

The Ilmor MV8 570 is a 454 CI engine based on GM LS architecture, with Ilmor designed forged internals. Variable valve timing and digital controls make for an efficient delivery of power on 91 octane. With a high RPM operating range 5500-6000, and a relatively light 830 Lbs with fluids, this is a really attractive engine. Paired with an Imco SC or SCX drive, or a Teague Platinum drive, you will often find the package comes in just under the price of the Mercury Racing package. Technically you could run a Bravo XR drive as well.

Everyone I’ve talked to about the MV8 says it’s very reliable and they love the performance, noting the RPM range and seat of the pants punch. Torque for the Ilmore is 564 lb/ft at 4400 RPM.

Key advantage; compact size, lighter weight, higher RPM range. A con for some might be the drainage for winterizing is not as accessible and it comes with a 1 year limited warranty.

Mercury Racing 565

Even thought the horsepower is basically the same, the Mercury Racing approach is a little different. Racing has gone with a larger displacement lower revving engine, at 533 CI (8.7L) and producing 610 lb/ft at 3600 RPM, you can immediately see how the engines differ. The Mercury Racing 565 makes it’s power lower in the band to, operating at 5000 to 5500 RPM. Both engines are CARB 3 star certified, where the Merc can burn 89 octane.

Some of the advantages would be seen if you have a heavier boat, needing more low end power, the Racing 565 has that. On top of that, the price, 2 year warranty and Mercury’s extensive service network.

Other really cool things about both engines is that they both look really amazing, with custom colors available. Ilmor offers a dress kit that polishes metal parts and adds sport tubular exhaust and custom engine covers. With a light really fast boat, the Ilmor can give you an advantage with 500 more RPM of rage and making power up top. But if you have a slightly heavier hull, you may opt for the big torque of the Mercury Racing 565.

Of course there are custom engine builders that make engines that are similar in power but these two warrantied powerhouses come at a great price and proven performance. There is no guesswork. I’m glad we have options like these, among others because I still love the power and sound of a big V8. A sterndrive boat has a certain look and feel too that is different than an outboard. In some cases for mid size sport boats, a powerful single sterndrive offers the right advantages. And if you’re repowering, these are great options.