The LS series is the third generation of the chevy 350. First generation was the 350 chevy, second generation was the Lt1, and the third generation or the "LS series" is the Ls1, Ls2, Ls7.... The LS series is just the 350 all grown up with power, reliability, looks, sound, performence, not that the prior 350's weren't great, but the LS1 is what, 400hp stock?