NEWARK, N.J. -- Yo, Sly: Pay up!

Former heavyweight boxer Chuck Wepner unleashed a legal roundhouse Wednesday against actor Sylvester Stallone, claiming the "Rocky" movie series was based on Wepner's own career. Now he wants a piece of the purse.

Wepner, who went nearly 15 punishing rounds in a 1975 loss to Muhammad Ali, claims in a lawsuit filed Wednesday in state Superior Court in Jersey City that Stallone repeatedly credits that fight as the inspiration for the film that won the 1976 Academy Award for best picture.

But when it came time for sharing the riches that followed, Wepner claims, Stallone treated him like just another bum from the neighborhood.

"Stallone has been using Chuck's name -- and continues to this day -- in promoting the "Rocky" franchise without any permission or compensation," said Wepner's attorney, Anthony Mango. "They're doing that to add an element of authenticity to the sale of these products."

Mango estimates the five "Rocky" films and associated products have brought in over $1 billion. Wepner is entitled to part of that, he added.

"It's one thing to base a movie on someone, which you can do," Mango said. "It's another to continually harp on the name for selling and promoting without any permission or compensation, which you can't do."

Stallone's publicist, Michelle Vega, declined comment on the suit.

"Rocky" was the story of a down-and-out club fighter from Philadelphia who got a longshot chance at boxing's heavyweight title when reigning champ Apollo Creed was looking for a patsy for his Bicentennial fight. Stallone played Rocky Balboa, who worked at a meat-cutting plant and nearly dethroned the champ.

Wepner was a New Jersey club fighter who ran up a string of victories and eventually caught the eye of boxing promoter Don King. Wepner was nicknamed "The Bayonne Bleeder" for the punishment he was prone to receive even while winning.

After Wepner knocked out Terry Henke in the 11th round of a 1974 fight in Salt Lake City, Utah, King offered him a title shot against George Foreman, who was the reigning heavyweight champ. But when Ali defeated Foreman, Wepner got the match with Ali.

On March 24, 1975, the two fought in Richfield, Ohio, and Wepner knocked Ali down in the ninth round. Ali eventually scored a 15th-round technical knockout of Wepner with 19 seconds remaining in the fight.

The lawsuit claims Stallone made several promises to Wepner that he would be financially compensated over the years, but no payments were made, Mango said.

Wepner now lives in Bayonne, and works as a liquor salesman.