Thin epitaxial carbide films have been deposited in UHV by co-evaporation of Mo. Nb, Ti and V, with C-60 as carbon source. Two separate systems were studied, Ti1-xVxCy on MgO(001) and Nb1-xMoxCy on MgO(111). We demonstrate the possibility to tune the cell parameter of an epitaxial ternary carbide film by control of the composition. Analysis with reciprocal space mapping show that deposition of Ti0.34V0.66C0.81 at 500 degreesC yields a strain-free film with perfect match towards the MgO(001) substrate, Also, a good manual control of the individual fluxes allows the design of tailor-made compositional gradient structures. An epitaxial linear carbide gradient film going from TiC to VC was deposited at 500 degreesC. Furthermore, the low deposition temperature allows the deposition of metastable carbide structures. This was shown with epitaxial growth of a Nb1-xMoxCy film at 500 and 600 degreesC.