In an era where turbochargers are dominating everything from small city hatchbacks to hypercars and track beasts, the large naturally-aspirated engines are a fresh breeze. It’s easy to understand our excitement that Mercury Marine, a manufacturer of inboard and outboard marine engines, has just launched a new high-performance crate engine through its Mercury Racing performance division.
Let’s start with the important numbers. The SB4 is a 7.0-liter small-block NA motor, generating 750 horsepower (559 kilowatts) at 8,000 rpm, while peak torque is 570 pound-feet (773 Newton-meters). It uses General Motors’ LS7 block combined with a newly-designed set of aluminum DOHC (dual overhead cam) cylinder heads. Thanks to the additional two valves to each cylinder, the engine is some 245 hp (183 kW) more powerful than the official LS7 numbers.
According to the official information, the engine is capable of operating with customer supplied manual or automatic transmission. It runs on unleaded 91-octane fuel and requires 6.5 liters of premium synthetic 15W-50 oil for warm weather use.
If you’re already impressed, there’s more good news. Mercury will sell the engine as a turn-key product with the necessary ECU with the correct tune, and even components such as alternator, AC pump, pulleys, and belts are included. Optionally, you can upgrade to a carbon fiber intake manifold and have it painted in a custom color. Mercury will offer a limited 12-month warranty.
What’s the price? The engine manufacturer asks a cool $32,995 for the fully equipped V8 motor, which is considerably more expensive than the $14,837 General Motors wants for the stock 7.0L LS7 crate engine. But there’s a catch – GM won’t provide ECU or wiring harness, and if you upgrade it to the levels of Mercury’s engine, it will easily surpass $33,000. And there’s no warranty, of course.