A classic American car is driven down a Havana street. A club of passionate Cuban motorheads will restore cars like this one on “Cuban Chrome,” a new reality show on the Discovery Channel. (Pilgrim Studios)

It started as another wacky idea for a reality TV show. The pitch went something like this:

The heroes are Cuban car guys! Watch how they, against all odds, restore 1950s American roadsters marooned in Havana from before the revolution. Catch glimpses of real life on the forbidden island.

Unlike most projects hatched in Hollywood, this one had to be greenlighted by the U.S. government, specifically by Treasury Department officials responsible for policing the trade embargo against Cuba.

The feds panned the idea in 2013.

“We were denied,” says executive producer Craig Piligian, whose vast reality TV credits go all the way back to “Survivor” and “American Chopper.” “How do we un-deny it?”

Mechanic Hernan Montalvo works on an ancient Oldsmobile in "Cuban Chrome." (Discovery Channel)

After a year of lawyering and massaging the pitch, the producers were granted a license last summer from the Treasury under an exception permitting professional research for an educational documentary.

“We were off to the races,” says Piligian, chief executive of Pilgrim Studios.

The finished product, an eight-part series called “Cuban Chrome,”premieres at 10 p.m. Monday on the Discovery Channel. The show will air in 220 countries — just not Cuba, where Discovery is not distributed.

Discovery calls “Cuban Chrome” the first American television series ever shot entirely in Cuba. Really? The Washington Post put television historians at the Paley Center for Media in New York on the case. After consulting records from sources including the National Archives and the State Department, they say they can’t find any other examples. But Paley Center curator David Bushman did uncover notable one-off shows: Long before Conan O’Brien’s recent Cuban foray, in 1958 Steve Allen filmed a show at the Havana Riviera Hotel with Edgar Bergen and friends. The same year Jack Paar originated a show from the Tropicana nightclub, and the next year Paar interviewed Fidel Castro at the Havana Hilton.

“Our show is about cars, but it’s really about looking at Cuba through the lens of cars,” says Craig Coffman, Discovery’s executive producer for “Cuban Chrome.”

Demetrio Montalvo, center, and his sons Michel, left, and Hernan are three of the Havana car enthusiasts featured in "Cuban Chrome." (Discovery Channel)

Discovery’s interest started with Denise Contis, executive vice president for production and development, who saw Cuba as the next frontier for the network’s “Motor Mondays” lineup of car shows. She raised the idea with Piligian, who had separately fielded a concept from outside producers with Rhino Pictures.

When production began last summer, the two nations were still officially unfriendly. In one of those instances of cosmic luck that documentarians live for, the film crew was in Havana with the show’s characters on the December day when President Obama and President Raúl Castro announced their resolve to mend relations. In the fifth episode, there’s an emotional scene as the Cuban car guys and their families watch the live television announcement.

“This news we just heard, it changes everything,” Roberto Ordaz, one of the characters, says in that episode. “Personally for me, I’m having a baby, so I know the future is going to be better for all of us.”

“Cuban Chrome” centers on several members of the A Lo Cubano Car Club in Havana. “A Lo Cubano” means “Cuban style.” They are passionate devotees of Detroit’s classic masterpieces that last reached the island in about 1959, the year Fidel Castro toppled dictator Fulgencio Batista.

The boxy and big-finned old Chevys and Fords are so precious they are handed down within families. There’s a fortune in tourist taxi revenue waiting for anyone who can repair one, paint it a candy color and get it on the road. Resurrected dreamboats are parked in long rows outside the tourist hotels of Old Havana.

Yet these mechanics and hobbyists face a challenge unknown to motorheads almost anywhere else in the world: How do you keep old cars running when for more than 50 years, new replacement parts have been unavailable because of the embargo?

The answer: “Cuban physics,” Ordaz says in the show. “It’s how to solve problems. Not to get stuck, not to wait for anybody else. You can do it yourself.”

In practice, Cuban physics means making gaskets out of cardboard. It’s two mechanics riding a single bicycle around Havana in search of a steering part. It’s using a horse to haul an engine from the carcass of another car to replace the diesel boat motor that you have been using to run your baby-blue Oldsmobile.

And so we watch the plucky, ingenious Cuban car guys in their makeshift open-sided garages pursue the quests set up in the first episode: to restore three absolute wrecks to former glory. Failure means economic ruin, or worse, a loss of respect within the close-knit Havana car culture.

Along the way, the show detours into facets of Cuban life, such as a cockfighting exhibition — a nonlethal one, we are told; an explanation of Cuba’s curious dual currency system; a summary of Cuba’s real estate market. There’s no talk of politics.

Reality seems enhanced here and there. The main job of Ordaz, who signs on as assistant to master mechanic Fernando Barral, appears to be delivering perfectly timed explanations in English of what’s going on and what’s at stake. Barral, who owns a 1934 Model A hot rod, pays a guy named Papito the equivalent of more than $9,000 for a 1958 Chevy Bel Air. Barral says he’s been saving for years.

“There’s no better feeling than finding a car that’s in total disrepair and transforming it into one of the most beautiful cars in all of Havana,” Barral says in Spanish with English subtitles.

A week after the show premieres, a Cuban flag is scheduled to be raised for the first time in more than half a century over the newly reestablished embassy in Washington. And the American flag will fly in Havana.

The car guys may welcome this more friendly era — but it spells doom for a Cuban car show. If the embargo is lifted — Republicans in Congress still balk at that — finding car parts could be as easy as running to the Cuban Pep Boys on the corner.

That wouldn’t make good television.