VIN DIESEL wracked by guilt wants PAUL WALKER’s younger look-a-like brother to replace dead star.

FAST & FURIOUS” star Vin Diesel is riddled with guilt over the tragic death of co-star Paul Walker, but he doesn’t want to pull the plug on the billion-dollar franchise, a source says.

Diesel, 46, deeply regrets the petty squabbles and egotistical clashes that ruined his once-close rela­tionship with Walker, 40, according to an insider.

But Diesel desperately wants the blockbuster series to keep on rolling, the source says, and he’s on board with Walker’s younger brother taking his place in the wildly popular movies.

“Vin is shattered over Paul’s death,” a source told The ENQUIRER.

“He’s broken down in tears several times and said he wishes Paul would just walk in the door, tell him this was all a bad dream and forgive him.

“Vin has told friends he hates himself for feuding with Paul and feels terribly guilty about how he treated Paul while he was alive.”

On screen, Walker played an under­cover cop with Diesel’s char­acter, an ex-convict who’s also an elite illegal street racer, as his prey. Their relationship was at the heart of the fran­chise’s success.

But behind the scenes, that thrilling chemistry turned into an ugly rivalry, the source says.

“Paul and Vin really came to dislike each other,” said the source.

“Paul said Vin was always trying to outdo him on the set, stealing the limelight, upstag­ing him and fawning all over producers to make himself look good and Paul look bad.

“Paul also thought Vin was loud, brash and aggressive, while Vin thought Paul was a Hollywood wimp.

“That couldn’t have been fur­ther from the truth, but Vin thought he could walk all over Paul when it came to negotia­tions, and that infuriated Paul.”

The bad blood between the two exploded in 2009 when they were negotiating deals for the fourth “Fast & Furious” film, the source said.

Diesel was a producer on the film, and “their friendship died completely because Vin made a major cash-grab,” the source di­vulged.

“Paul said Vin was a ‘bully,’ and he had to fight Vin for every little thing in his contract. It got so bad that Paul brought his entire business and legal team along every time they had a business meeting.

“During their negotiations, Paul complained that Vin was standoffish and even borderline sinister.”

Both actors cashed in big-time thanks to their work on the franchise. But Diesel ended up with the bigger piece of the money pie, amassing a $60 million fortune compared to the $45 mil­lion Walker left behind.

Since Walker’s death in a fiery car crash on Nov. 30, Vin claims the two were like brothers. But nothing could be further from the truth, added the source.

 “Paul was close to several people on the set, but they were cameramen, stuntmen and other production people Paul genuinely liked,” the source noted. “He tried to keep his feuding with Vin out of the public eye for the good of the franchise, but when the cameras were off, Paul avoided him like the plague.”

Now Diesel is fretting that details of their real relationship will leak out and damage his image, said the source.

“He’s determined to make amends and he’s doing everything he can to help Paul’s family and to honor his legacy,” said the source.

“But Vin’s hypocrisy is making Paul’s true friends gag, because they know how nasty he was to Paul when Paul was alive.”

The “Fast & Furious” series has been a box-office bonanza, with the first six films making more than $1 billion in the U.S. and about $2.4 billion worldwide.

The last installment, “Fast & Furious 6,” was the biggest grossing movie of them all, pulling in more than $788 million worldwide. Industry insiders expected “Fast & Furious 7,” which was being filmed when Walker died, to top that by a wide margin.

Some feel the unfinished movie should be scrapped, but producers are scrambling to salvage it.

“ ‘Fast & Furious 7’ should be shelved as a memorial to Paul,” a source close to the film told The ENQUIRER.

But with mega-millions at stake, producers aren’t about to kiss that big money goodbye.”

Producers are reportedly planning to use Walker’s look-alike younger brother, 25-year-old stuntman Cody Walker, to complete the film.

But they have yet to craft a story line for the death of Walker’s character, Brian O’Conner, said the source.

“Script writers are scrambling to find a way to write him out of the series in a respectful manner,” the source noted.

“Most likely, they’ll film a scene of Brian O’Conner dying in ‘Fast & Furious 7.’

“There has even been talk about having Cody re­place Paul in the series in an ongoing role, playing Brian’s younger brother in an eighth film.”

That movie is already in the planning stages, but Cody’s role is not a sure thing, said the source.

“A lot of industry people and family members oppose Cody taking his brother’s place,” said the source.

“It is kind of creepy, but Vin is all for it. He sees Cody’s role as a way to honor Paul’s memory, and justify Vin continuing to cash in with the ‘Fast & Furious’ franchise.”