by Ron Wynn 　　You wouldn't expect any changes from George Thorogood, whose pile-driving rocking-blues and boogie have maintained their appeal despite the emergence of numerous similar-sounding ensembles. Thorogood's rough-hewn singing and always tantalizing playing are on target through the usual mix of originals and covers (this time including Bo Diddley and Willie Dixon). Besides the bonus of major label engineering and production, Thorogood's work has never lost its edge because he avoids becoming indulgent or a parody, and continues to sound genuinely interested in and a fan of the tunes he's doing.