OM X-series

Developed by OM, it was offered with a variety of different engines and with many different badges. The smallest versions used Fiat's 8040 four-cylinder diesel engine, and were marketed as Fiats, OMs or Unics in France. Mid-range versions (sold as OM or OM-Saurer) used the larger OM CO3 four-cylinder, developed together with Saurer of Switzerland. The heaviest models received Fiat's six-cylinder 8060 engine and were sold as Fiats or Unics, and also as the OM N100.

OM's versions were named with a two-digit code indicating gross tonnage ranging from the OM 35 to the 100, a system also used by Saurer on the versions they sold. The range was thus from 3.5 to 10 t (7,700 to 22,000 lb). Fiat and Unic used the same numerical system followed by NC (for Nafta Cabinato, "diesel cab-over"). Magirus-Deutz sold this range under their brand after 1975 and used their own air-cooled engines for some models (55, 60, 75).^[1] In Austria, this truck was marketed as a Steyr-OM.^[1] The X-series was also built by Zastava, beginning in 1978.^[2] Kits for the 35-40 were also sent from Zastava's plant by Iveco for CKD-assembly in Kano, Nigeria, by a company called NTM. These trucks received Fiat badging, as this brand was considered strongest in Nigeria.

The X-series cab was lightly facelifted a few years after its introduction, when the early metal grille was replaced by a black plastic unit with horizontal bars. The interior remained unchanged. "Iveco" badging also became more prominent after that company was founded on 1 January 1975. A more thorough redesign, with a new, more square cab, appeared in late 1976 and was called the OM Z-series. This replaced the earlier X lineup by 1977, although the Fiat 35/40 NC remained on sale until 1987 with the earlier cabin and it continued to be built by Zastava in Yugoslavia into the early eighties.

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  OM 40 moving truck
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  Fiat 40 NC, facelift model with plastic grille
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  Zastava 635AN