At the 1982 Geneva Motor Show, the Countach finally got the 5-liter engine it was originally design for. This was the first Countach update in four years, following a stepwise evolution of the model since the production version was introduced in 1974.
The 5000S was initially called the 500S, but this new moniker was somewhat misleading because the new engine only displaced 4754 cc. This increased power over the preceding 4-liter engine by 50 bhp.
Some later cars featured a new rear end with an extended trailing edge that lengthened the car by an inch or so. Over a three year period around 320 cars were produced.
The first 20 cars were fitted with Campagnolo Cast Magnesium wheels but these were replaced by Ozzeta Electron units.