Rolls-Royce (and Packard) built almost 150,000 27-liter Merlin V-12 engines during World War II. Many of them survived, yet none were supposed to end up in road cars. But then came a bunch of aero engine enthusiasts, one of them being Jay Leno. And so a 25-year-long quest began, with the goal of turning a 1934 Rolls-Royce into a Merlin-powered monster machine.
And how much torque would such a car provide? “Like the hand of God, it just pushes you,” says Leno.
Leno, who also owns a Rolls-Royce Meteor-powered Bentley, bought this car from a British gentleman almost three decades ago. It was a Rolls lacking a permanent body and, among other things, a gearbox that could take the torque (the Jaguar XK120 unit that the car came with certainly couldn’t). So Leno enlisted his chief fabricator Jim Hall, whose first task was to figure out how to put six twin-Weber carburetors on a Merlin. Hint: You’ll need a 3D-printer.
On top of creating a period correct aluminum body with a grille that doesn’t look out of place on a Rolls, Leno’s team also upgraded the chassis with a six-speed manual New Venture Gear 5600 transmission—the same one found in Cummins-powered Ram pickup trucks. Various other bits helped this backwards-mounted engine adapt to its new, close-to-the-ground career. Now, this 1934 chassis has additional electric cooling pumps, stronger wire wheels, an upgraded Dana 60 rear axle with a custom driveshaft, a 24-volt electrical system and two 30-gallon fuel tanks. But it retains its hand magneto for the traditional “shower of sparks” experience.
With the Merlin engine alone weighing some 1800 lbs, this aero monster is a 4800-lb. beast with no brake booster in sight. Yet Leno has already put more than 800 miles in it, presumably giggling all the way. He’s been waiting 25 years for this.