In 1968, Ferruccio Lamborghini was somehow forced to replace the 350/400 GT model, the Carrozzeria Touring was falling into great financial troubles at that time, so Ferruccio released the Islero.
By 1970 things were going great and Lamborghini could start thinking about second generation models, the Jarama is in fact a mark II Islero, it had completely different looks, but it was aimed at the same public, the wealthy who didn't want to show off, because if you wanted to be noticed you'd buy a Miura.
The Islero had to be replaced to comply with the American Safety and emission rules, Chief Engineering Gianpaolo Dallara left Sant'Agatha at the time so for the Jarama project Paolo Stanzani was in charge, he decided to use a shortened Espada chassis to mount a new body on.
This body was again designed by Marcello Gandini, while it was to be built by Marazzi, the latter both designed and built the Islero. Because he only shortened the Espada chassis by 10.7 inches, the new Jarama spanned a rather wide track, this resulted in a low, wide car, with wheel arch flares, two NACA ducts in the hood (just like the Espada) and four headlamps, who were partly concealed by metal lids. These lids didn't pop up as a normal concealed headlamp, but they were electrically powered down.
Although the Jarama was a lot heavier than the Islero, the claimed top speed remained the same, but the workmanship on the first series Jarama left much to be desired, it changed with the second series, the 'S'-model, but the public opinion was already made, the Jarama is one of the forgotten Lamborghinis, subsequently only 177 Jarama were built between 1970 and 1972.
The LamboCARS.com extensive specifications chart on Jarama GT 400 ...