We consider methods to locate sync words in packet or frame transmission over the additive white Gaussian noise channel. Our starting point is the maximization of the probability of correctly locating the sync word. We extend Massey's original result to the specific synchronization problem, where the sync words is prefixed to the data stream and each packet is preceded by idle transmission or additive white Gaussian noise. We give simulation results for several interesting sync words such as Barker sequences of length 7 and 13 and a sync word of length 17 with good cross-correlation properties. One of the conclusions is that the newly derived formula for the probability of correctly locating the sync word enables the reduction of the false sync detection probability.