[2] The car's namesake, Islero, was a Miura bull that killed matador Manuel Rodriguez "Manolete" on August 28, 1947.

[5] The design was essentially a rebody of the 400 GT, with its good outward visibility, roomier interior, and additional soundproofing improving driver and passenger comfort compared to previous models.

There were quite a few styling changes, including six engine cooling vents on both front fenders (hinting at the twelve cylinders within), an enlarged hood scoop (which supplied air to the interior of the car, not the engine), slightly flared fenders, tinted windows, round side-marker lights (instead of teardrops on the original), and a fixed section in the door windows.

Various other changes included slightly increased power output, larger brake discs, revised rear suspension and revamped dashboard and interior.

The car was equipped with upgraded brakes and suspension, modified air intake and exhaust system, a roll cage, a 100 litres (26 US gal) fuel tank, five-point harness, lighting for the racing number and hood straps.

[2][12][13] The Islero had a 325 bhp (242 kW; 330 PS), 3.9 L (3929 cc) Lamborghini V12 engine, as was also used in the 400 GT, Miura, Espada and Jarama.

The Lamborghini-designed five-speed manual transmission was equipped with synchromesh and a hydraulically operated dry clutch.