OUTSIDE THE courthouse last month, Joseph Merlino laughed off his upcoming prison stint as an opportunity to take his workout routine to the next level and "get my sixpack back."

But, come on, do you really think "Joey Sixpack" wants to spend four months doing crunches in a jail cell?

Lawyers for the ex-mob boss are asking for a postponement of his sentence while they appeal a judge's ruling that he violated the terms of his probation while living in Florida.

At a court hearing on Oct. 24, U.S. District Judge R. Barclay Surrick ordered Merlino to report to prison on Nov. 24 after detectives testified that he'd been spotted with John "Johnny Chang" Ciancaglini in a Boca Raton cigar bar in June. Merlino was on supervised release for his 2001 racketeering conviction.

Merlino's lawyers claim in a motion filed late Wednesday that the Ciancaglini meeting was a "chance, casual encounter," not a "planned and prolonged" meeting that would constitute a probation violation. They also are arguing that the feds failed to issue an official violation summons prior to the end of Merlino's supervised release Sept. 6.

Assistant U.S. Attorney David Troyer, who maintains that Merlino is still an active member of La Cosa Nostra, said yesterday that prosecutors would fight the latest motion.

"The judge ordered him to report in 30 days," Troyer said. "He should report in 30 days."

Meanwhile, the new Boca Raton restaurant where Merlino will be working - it's called Merlino's - apparently has opened for business. It sounded packed last night when the Daily News called.

"He's not in tonight," a woman said, before taking a message for Merlino.

The restaurant's owners include Florida businessman Stanley Stein, who testified last month that he had offered Merlino a full-time job as a "maitre d' or host." Merlino's lawyer, Edwin Jacobs Jr., has said that his client might be more of a manager there.

"We're gonna have the best Italian food in South Florida," Merlino had said after his last court hearing. "All my mother's recipes."

The cocktail menu includes the $14 "South Philly Beet Down" with dry gin, beet, ginger and lemon, and the $16 "Olde City Fashioned."

For dinner, try the $19 Gnocchi Mamma Rita, named after Merlino's mother.

The after-dinner-drink menu includes everything from a $9 tawny port to a $500 whiskey drink called "The Experience" with whiskey from now-closed distilleries.

Too rich for your blood? Compromise. The blend of 1,200 cognacs that are between 40 and 100 years old goes for just $240 for 2 ounces.