Degenerate four-wave mixing in the sub-Doppler phase conjugate geometry was used to record high resolution spectra of the d (3)Pi(g)-a (3)Pi(u) (0-0) Swan band of C-2 produced in an oxy-acetylene flame. The line positions of isolated transitions were measured to an accuracy of similar to 3X10(-3) cm(-1) and calibrated using a Fizeau interferometer system. The data obtained from these spectra was used to calculate rotational constants and lambda doubling parameters for the (3)Pi states from which the line positions for the whole band were calculated. Noticeable improvements between experimental and calculated line positions are seen when compared to previously published values. The effect of inaccuracies in line positions on the simulation of degenerate four-wave mixing spectra is discussed and some examples of the improvement in simulation using the newly calculated line positions are presented.