We present a systematic study of the Raman modes of a ferromagnetic series of manganites, La-1/3(Ca1-xSrx)(1/3)MnO3 with 0 <= x <= 1, that presents two different regimes for the variation of the ferromagnetic order temperature, T-C, with Sr doping. This change occurs for x similar to 0.5 when the temperature of the orthorhombic, Pbnm, to rhombohedral, R-3c, structural phase transition, T-t, coincides with T-C. We have analyzed the evolution of the frequencies and widths of the observed Raman modes as a function of Sr doping and temperature. At room temperature, features of the Pbnm structure are detected for compounds up to x = 0.6, over the orthorhombic phase limit x = 0.45 at 300 K. Octahedra bending modes behave as expected with doping while the tilt mode, which is related to Mn-O-Mn angles and therefore to electronic conduction mechanisms, presents different behaviors in both structures. The tilt frequency is much less sensitive to Mn-O-Mn angle in R-3c than in Pbnm structure indicating a reduction of electron-phonon coupling. Its width presents an anomalous behavior both as a function of doping and temperature with unexpectedly large width in the rhombohedral phase. (C) 2007 Elsevier B.V. All rights reserved.