Here you can find an all-electron basis set for group 14 elements: C, Si, Ge Sn, and Pb. The contraction coefficients were reoptimised with a relativistic method (RESC). It is a modified WTBS basis set of roughly cc-pvtz quality and it is given in GAMESS format. Check GAMESS manual for details. Briefly, exponents are followed by contraction coefficients. Note that l-shells are s and p-shells expanded over the same set of exponents with separate contraction coefficients, first s and then p contraction coefficients are given in each row. You must use internal uncontraction in the resolutions of the identity ($RELWFN uncon=1 $END) when using this basis set. For all details and references check the following paper that you are requested to quote if using this basis set:

W. Lie, D.G. Fedorov, K. Hirao, J. Phys. Chem. A, submitted for publication.

The basis can be taken from here.