The dynamics of Pd-based metallic glass-forming liquids (Pd40Ni10Cu30P20, Pd42.5Ni7.5Cu30P20, Pd40Ni40P20, and Pd30Ni50P20) was studied by mechanical spectroscopy and modulated differential scanning calorimetry (MDSC). We found that the change in composition has a significant effect on the alpha relaxation dynamics; the largest difference corresponds to an increase of the glass transition temperature T-g of similar to 15 K, for materials in which 30% Ni was substituted by 30% Cu (i.e., from Pd40Ni40P20 to Pd40Ni10Cu30P20)). We also found that all Pd-based metallic glasses have very similar fragilities, 59 < m < 67, and Kohlrausch stretched exponents, 0.59 < beta(KWW) < 0.60. It is interesting that the values of m and beta(KWW) correlate well with the general relation proposed by Bohmer et al. for nonmetallic glass formers (Bohmer, R.; et al. J. Chem. Phys. 1993, 99, 4201-4209), which for the observed beta(KWW) values predicts 58 < m < 61. From a linear deconvolution of the alpha and beta relaxations, we find that the substitution of the Ni with Cu induced a large change in the time constant of the Johari-Goldstein relaxation, tau(beta). The activation energy, U-beta, of the beta relaxation was largely independent of chemical composition. In all cases, 25 < U-beta/RT < 28, a range in agreement with results for other glass formers (Kudlik, A.; et al. Europhys. Lett. 1997, 40, 649-654 and Ngai, K. L.; et al. Phys. Rev, E 2004, 69, 031501). From the heat capacity and mechanical loss, estimates were obtained for the number of dynamically correlated units, N-c; we find significantly larger values for these metallic glass-forming liquids than N-c for other glass-forming materials.