When it comes to crate motors worth dropping into road-going speed machines, Mercury Marine likely isn't the first name that comes to mind. (A fact which likely has quite a bit to do with the word "Marine" in there.) But in spite of its aquatic roots, the company has a bit of history building sweet engines for high-performance cars. It was Mercury Marine, after all, that handled assembly of the Lotus-designed DOHC V8 that hid beneath the C4-generation Chevrolet Corvette ZR-1's hood.
In recent years, the company has begin making more of a point of showing off how nicely the assorted wares produced under its Mercury Racing brand work in an automotive context. Back in 2015, the company modified a twin-turbocharged 9.0-liter V8 for duty in SpeedKore Performance's carbon fiber-bodied '71 Dodge Charger known as "Tantrum." In that SEMA-spec muscle car, Mercury's motor cranked out a seismic 1,650 horsepower.
Cut to the present day, however, and the company has launched its latest foray into crate engines specifically designed for automotive use. It's a little more tame than the Bugatti-beating engine crammed into the Tantrum...it's hardly a wimp.
The Mercury Racing SB4 is a 7.0-liter four-valve-per-cylinder small block engine based on the beloved LS7 V8 found in the C6-generation Corvette Z06 and the former Camaro Z/28. The LS's in-block cam and pushrods get the old heave-ho, replaced with Mercury Racing's own dual-overhead-cam valve train. Thanks to engineers careful handiwork, the SB4 revs to 7,500 rpm and cranks out a stunning 750 horsepower—about 50 percent more than the engine it came from.
In order to help get the word out about the new Corvette-based engine, Mercury invited The Drive out to the company's Wisconsin headquarters (or, to be more accurate, a closed-off airstrip nearby) so we could have a chance to open the taps on the SB4. And since bench-racing an engine is only fun for nerds, the company gave us a chance to test it out by driving an Ultima GTR—a mid-engined track machine that weighs roughly as much as a Mazda Miata—equipped with the manic small block between its axles.
What was it like? Well, hit play and find out.