The head itself is made in three pieces, one carrying the combustion chamber and valves and one separate casting for each camshaft in tunnel type bearings.

Usually at that time in double overhead camshaft engines like from Alfa Romeo or Jaguar, small shims were placed on the valve stem inside the bucket tappets, thereby necessitating the removal of the camshafts to get access to these shims to adjust the valve clearance, making for time consuming and very expensive maintenance work.

Fiat was a pioneer in engine development during the time period, using toothed rubber belt driven camshafts and aluminium alloy heads.

Lampredi's twin cam engine was first seen in the Fiat 124 coupé of late 1966, but was later made available in a large number of cars.

Therefore, the homologation series of the Fiat 131 Rally Abarth came with a two-litre version of the four valve engine.