"PACK UP THE PLANTATION." Tom Petty & the Heartbreakers. MCA. Until last year, Petty had a reputation for rehashing his recordings in concert without much fire or imagination, but his 1985 tour wisely updated much of his older material in the musical framework of his then-current "Southern Accents" album, with heartening results. He didn't try out anything nearly as radical as Dylan's "Live at Budokan" rearrangements--a horn section and female backing vocalists were his major changes--but the new elements were enough to make a classic early song like "American Girl" sound as fresh and vigorous as on the day it came out. Much of the standard material from that tour has been left out of this live double album, and more than a quarter of the set is taken up by choice remakes of '60s hits ("So You Wanna Be a Rock 'n' Roll Star," "Stories We Could Tell"). While that keeps "Plantation" from living up to its potential as a brave reappraisal of Petty's career, his dip into other folks' careers is far from tragic.