Mercury Shows Off 32-Valve LS V8 at SEMA

Dual-overhead-cam LS7-based engine headed for swaps with the Roadster Shop and others.

Mercury Racing has touted their LS7-based dual-overhead-cam V8 for several years, but the 32-valve engine appears production ready, as Power Automedia showed at 2017 SEMA Show.

Capable of turning up to 8,000 rpm and producing 750 horsepower, this new 7.0-liter V8 should make for some great swaps. Mercury calls it the SB4 7.0 and while it shares similar bottom-end architecture to the LS7, it very much represents a new engine.

Mercury designed a bespoke intake manifold for the car with twin 80-millimeter throttle bodies. The company has changed the internals to deal with the high revs, which also will include improved oiling. Mercury designed the ECM to control the fuel injection, as well, although transmission control will require standalone support.

Size factors as a consideration in any DOHC V8. However, the SB4 7.0 actually sits shorter overall compared with a stock LS7. It does stretch out 1.5 inches wider, but that shouldn’t change applicability in most instances.

If it sounds familiar, we wrote about it last year and Mercury had prototypes at the SEMA Show in 2014. Recently, however, they’ve tested the SB4 in an Ultima GTR with some fanfare.

Perhaps more importantly, Mercury has partnered with the Roadster Shop in suburban Chicago. That famous custom shop likely will start using the SB4 7.0 to make wonderfully driveable custom cars to its high standards.

While Chevy has made waves recently with a new 755-horsepower LT5 —which may or may not be DOHC — in the C7 Corvette ZR-1, GM first used the LT5 engine name with the C4 ZR-1. Mercury built that DOHC V8 to make more than 400 horsepower, a massive sum for the time period.

Even if the new LT5 is a 32-valve engine, it likely won’t be available as a crate engine for some time. So the Mercury SB4 might be your only DOHC option for swaps for some time.