The iconic Biff Burger in St. Petersburg could be closing if the stars don’t align for the longtime classic burger joint on 49th Street near 38th Avenue North. The restaurant’s former owners, George and Sandra Musser, are suing to foreclose on the property and restaurant because the new owners are defaulting on payments.

The historic burger and barbecue spot opened in 1960 as part of a pretty large chain that later disintegrated after Burger King bought most of the franchises. The Musser’s kept their Biff Burger, which is an acronym for “best in fast food,” and it has been a staple of the hot rod and classic car community for decades. On Friday nights, proud car owners line up with their supped up Ford Mustangs and old school Chevy Camaros, among others.

But the aging couple sold the business in 2015 to Raphael Prezioso and his family for an undisclosed sum. Since then, the lawsuit alleges the family has missed payments on the $600,000 mortgage for which the Musser’s still hold the note.

The property and restaurant would be sold to the highest bidder at auction if the foreclosure goes through and the new owners would then have to decide whether to keep the restaurant open, according to the Musser family attorney Howard Ross.

The lawsuit lays out a series of payment defaults to vendors and claims the financial stewardship of Biff Burger has been so bad some vendors have refused to supply the business even on a cash-on-demand basis. Additionally, the Musser’s claim the business has scaled back on wait staff and shrunk the restaurant’s menu and that the restaurant “is deteriorating both physically and in patronage and reputation.”

Ross said the foreclosure suit is “longer than most” because it includes so many allegations of mismanagement and delinquent payments. He said it’s impossible to tell how long the proceedings may take, but if it progresses without too much pushback from defendants, it could take a year. If there is a more detailed defense strategy, Ross said it could take longer.

Ross has not been in contact with the defendants on the case, he said. Rafael Prezioso did not immediately respond to a request for comment.

Biff Burger isn’t just known for its Friday night classic car get togethers. The restaurant also hosts popular bike nights on Wednesdays and Saturdays. It’s also popular for its hearty burgers with a well-guarded secret sauce recipe consisting of ketchup and several other spices.

The drive in and restaurant also serves barbecue and sundaes and milkshakes, making it a popular spot for families as well. It’s one of a handful of historic restaurants still operating in Tampa Bay.