After ISO founder Renzo Rivolta passed away in 1966, son Piero Rivolta took over the company that produced the Rivolta GT and Grifo sports coupe. It became his mission to grow the brand and fill out Iso’s product portfolio. He introduced the four-door Iso S4 (later badged Fidia) in 1967. Designed by Giorgetto Giugiaro (now at Ghia) and built on a stretched version of the Iso GT/Grifo platform, it showcased proven carryover powertrains. The prototype S4 was on the cover of the September 1967 issue of Quattroruote magazine while actual production didn’t start until February 1968.
In production into 1974, it was available first with 327 and 350 Chevrolet small-blocks and later with Ford 351 Cleveland engines. Transmission choices included four and five-speed sticks and automatic. Depending upon rear end gearing, top speed was 125 to almost 150 mph. It was truly impressive performance for a four-door sedan.
Early S4s were plagued with quality issues and poorly finished interiors. Its platforms were built at Iso’s Bresso plant and then shipped to Ghia in Turin for body and interior installation. Cars were then shipped back to Bresso for powertrains and running gear and final assembly. S4 performance was excellent, but Piero Rivolta could not accept the poor fit and finish of the bodies and questionable Mohair interiors. In February 1969, Rivolta introduced the updated and re-trimmed S4, badged Fidia. Interiors were leather and quality issues were cleared up. Piero Rivolta finally had a four-door sports sedan he could be proud of.
Sports Car magazine in Australia really loved its Fidia test car, “Italians are known for their rare and fine cars. The Iso Fidia is one of the rarest, and as a touring car, one of the finest.” Total 1967-1974 S4/Fidia production: 192.
One of the early Iso sales brochures had this to say about the Iso Rivolta S4/Fidia: “The car which not only gives satisfaction to the driver but assures the maximum safety and comfort for his family. Here are the four most prestigious seats in the world.” Later Piero Rivolta changed “Prestigious” to “Fastest” in Fidia advertising and sales brochures.
Iso Rivolta S4, 1967-69
Iso Rivolta Fidia, 1969-74
Images: Andre LE ROUX Site; www.carguychronicles.com