A free-flowing intake and heads, aggressive cams and high compression did a lot of heavy lifting while the exotic flat-plane crank grabbed headlines and helped make lyrical exhaust sounds
The engine produced 526 naturally aspirated horsepower at 7,500 rpm and 429 lb-ft of torque at 4,750 rpm, while making beautiful music up to an 8,000-plus rpm redline. At the heart of its howling exhaust note was a flat-plane crankshaft — so called because its connecting rod journals (and weights) were positioned 180-degrees opposite of each other, instead of at 90-degree intervals like the cross-plane design used in most American V-8s. Flat-plane cranks are not new or unusual. Four-cylinder engines have them and Cadillac’s 314 V-8, which debuted in 1915, used one.
In theory, the flat-plane design delivers a V-8 with less reciprocating mass, and superior breathing, which should make an engine lighter, more compact and capable of building rpms very quickly. But it also delivers a lot of what’s known as “secondary vibration” and that paint-shaker quality increases in proportion to the size of the pistons and the speed that those pistons are moving. In a race car, it’s a reasonable tradeoff – especially if there’s a performance advantage to be gained. In a 21st-century street car, stickering north of $60,000, customers are likely to complain about shaking steering wheels, buzzing shifters, blurry rearview mirrors, etc. So, Ford incorporated bits on the GT350 that you wouldn’t find on a race car, like exhaust dampers and a dual-mass flywheel, to help smooth things out.
While the Voodoo’s flat-plane crankshaft grabbed all the headlines, this engine would’ve made tremendous horsepower if it had been built with a cross-plane crank. It inhaled through an 87-millimeter throttle body, the largest ever used on a Ford engine. The cams were aggressive, producing .55 inches of lift with 270 degrees duration and using low-friction roller followers to bump the valves. Compression is key to making power and, with a lofty 12:1 compression ratio, the Voodoo had plenty.