Transforming a standard Lamborghini 4.0L to a larger size was a real challenge. In order to increase the stroke from 62mm to 80mm required that the deck of the block be raised by 9mm by the use of custom deck plates. After the block was raised, then many other factors are changed as well (cam chain, head studs, tensioner sprocket, liner length, etc.). Additionally, the cam profiles had to be re-designed for low rpm (1,500 to 5,500 rpm range). When the engine was dyno tested, the Weber carbs needed to be completely re-calibrated for the larger displacement and lower rpm running range. All of the modifications were successful and the engine made good low rpm torque which is essential for a marine application. This engine and the sister counter- rotating engine will be installed in a Riva Aquarama speedboat once owned by Mr. Lamborghini.
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Power: 322-hp @ 5,100-rpm, 379 lb-ft of torque @ 3,600-rpm
Type: V-12, DOHC 2v/cylinderBore: Razzo Rosso forged pistons/big-bore liners, 85mm
Stroke: Razzo Rosso billet stroker crank, 80mm
Compression ratio: 10:1
Cylinder heads: intake ported and matched, new exhaust valves
Camshafts: special Razzo Rosso profiles for low-end torque
Induction: Six Weber 40 DCOE carbs with 32mm venturis
Exhaust: special marine wet manifolds
Ignition: Pertronics electronic ignition
