White Kyurem's 125 HP, 170 SpA, and 100 SpD combine for 395, which is the highest combination of any Pokemon from the first five generations. Discounting it, the highest would be Kyogre, with 100 HP, 150 SpA, and 140 SpD combining for a total of 390.
Groudon's 150 Atk, 140 Def, and 90 Spe combine for 380, and that's the largest total (from the first five generations) of those three stats combined.
These are the highest I could find from looking at raw stats and adding them manually. If there's something higher that I missed, please let me know.