This V-16 Resurrects a Forgotten Engine Architecture for a Custom Build

“If you have two V-8s that are exactly in the same timing, your pistons aren’t firing properly; it can rip itself apart—not good.” That’s Bryan Fuller summarizing the challenges presented by physically joining a pair of LS3 V-8 engines to create an 854 cubic-inch V-16 reported to make in the neighborhood of 1200 horsepower.

But while getting 16 holes to fire in a complementary, non-destructive manner is a feat unto itself, the impetus behind the project is a one-off custom Roadster designed by Hot Wheels with direct input from the unnamed, ostensibly well-heeled client. Fuller says the design of the 19.5-foot-long custom roadster is inspired by the 1938 Cadillac V-16 Series-90, but devotees of the brand’s history will recognize the spirit of the 1937 Cadillac V16 Hartmann Cabriolet, a two-off run of vehicles crafted in Switzerland for—you guessed it—a wealthy client.

For Sale Near You

See all results for used cars for sale near h3h 1a2

Back in the 21st century, Fuller had to address the timing, cooling, fuel, and air issues, as well as engineer their structural unity and their combined output to ensure the V-8s play nicely together.

As for ignition timing, the rear engine is clocked back “about 45 degrees,” which allows the tandem V-8s to fire in the proper order of a V-16. A single starter spins both. The mating of the torque is achieved by mounting a giubo joint (a.k.a. flex disc), a flex joint comprised of a rubber or urethane center with metal mounting plates on either side that mates the rear of the front engine with the front of the rear engine. Structural connection of the V-8s is made via a trio of CNC-machined plates, one in the center valley and one each on the lower right and left sides.

Ignition is handled traditionally, with two computers and individual plug wires, Fuller noted that “the LS3 is a known quantity,” and years of tuning the LS3 V-8 makes the job a little easier. Cooling is the only shared major system. A Meziere water pump generates enough pressure to move the coolant through both engines, out a custom dual outlet, and into a single radiator. Air is handled by a highly modified Holley intake that will continue to be modified as the project moves to installing the powertrain in the body.

The Tremec T-56 Magnum transmission was optimized by Bowler Performance Transmissions, who polished the internals, among other tweaks. As expected, ARP hardware is utilized throughout the project. Even the powertrain table it sits on is custom-built.

For Sale Near You

See all results for used cars for sale near h3h 1a2

At this point, the V-16 is waiting for the Roadster Shop to finish the custom chassis so the team can begin the process of combining all three elements to create a fully operational vehicle. How long that process will take is unclear, but the V-16 makes a pretty nice conversation piece just as it sits on its custom display stand.

➡️ Skip the lot. Let Car and Driver help you find your next car.

Andrew Wendler brings decades of wrenching, writing, and editorial experience with numerous outlets to Car and Driver. His work has appeared in numerous publications, including Car and Driver, Esquire, Forbes, Hot Rod, Motor Trend, MPH, MSN, and Popular Mechanics, among others. A Rust Belt native and tireless supporter of the region, he grew up immersed in automotive, marine, and aviation culture. A lifetime of hands-on experience and a healthy dose of skepticism provide him the tools to deliver honest and informative news, reviews, and editorial perspective. Of note, he once won a $5 bet by walking the entire length of the elevated People Mover up track that encircles downtown Detroit.

SEMA