It’s no coincidence that Tom Petty and his trusty Heartbreakers have followed a ferocious four-CD comp of concert highs (last year’s must-have Live Anthology) with one of their loosest, rawest, most expansive albums ever. The 15-track Mojo, released this week, is fat and greasy with Southern cooking and midnight sin. In other words, it sounds like Booker T. & the MGs dragged into a bar fight — or maybe the Grateful Dead packing heat. There are no fancy overdubs, no studio trickery. It’s just pure.

Despite all that critical gush, however, I should offer a warning: Mojo is for Petty diehards only. TP stopped writing hits years ago. The only thing here even mildly hook-based is I Should Have Known It, which would have been perfect for the radio dial...in 1972.

Instead, on such rollicking blues-rock jams as Jefferson Jericho Blues and Running Man’s Bible, Petty lets his venerable backing band run rampant, especially guitar god Mike Campbell and organist Benmont Tench, each of whom is boogie-down proof that some rockers really do get better as they get older.

On such cuts as Takin’ My Time and The Trip to Pirate’s Cove, the snarling, sneering Petty looks back — wistfully, maybe even regretfully — but he’s not giving up. Despite a late career marred by drug rumors, divorce and a smattering of creative fizzles, Petty has learned to have fun again, as both Candy and the reggae riff Don’t Pull Me Over attest. The whole thing sounds as if it was recorded in one room, in one take, with one flickery lightbulb illuminating the smirky, dangerous chaos. Enjoy the buzz.