A nodular cast iron alloy for cast iron products having a high modulus of elasticity comprising the chemical constituents C, Si, Cu, Ni and/or Mo, Mn, Mg and S, wherein the alloy is composed in per cent by weight of: C<2.96%, Si 3.8 to 4.3%, Cu 0.5 to 1.0%, Ni and/or Mo 0 to 4%, the molybdenum content being at most 1.0%, Mn 0.1 to 0.8%, Mg 0.03 to 0.07% and S at most 0.015%, the mixture proportions of C and Si being very close to the eutectic.