Now they are Nextel Cup teammates at Chip Ganassi Racing with Felix Sabates.
A 34-year-old from Scotland and a 32-year-old from Bogota, Colombia.
Who would have thought?
"They've always been attracted to NASCAR," Montoya said of international drivers as he watched Wednesday's press conference introducing next season's driver of the No. 40. "The hardest thing about it is it was seen as a very American sport.
"If you were an American, you were in. If you were not American, you were not. Nobody ever committed full time to it until I did. When I came and committed and things have panned out pretty good, people go, 'Oh, this is great.'"
Franchitti was supposed to be the leader of this international pilgrimage that also includes Jacques Villeneuve, the former Indy 500 champion who will make his Cup debut this weekend at Talladega Superspeedway for Bill Davis Racing.
He had discussed extensively with Ganassi plans to drive the No. 42 car this season until a late phone call from Montoya knocked him out of that ride.
It turned out to be a blessing in disguise as Franchitti won the Indy 500 and the IRL title, the latter edging Ganassi's Scott Dixon when Dixon ran out of gas on the last lap of the season finale.
"I'm betting you wish I'd come over," Franchitti jokingly told his new boss as the story was relived.
Ganassi called it a win-win situation. He now has Franchitti and Montoya, making his organization the poster child for NASCAR's international move.
Montoya won earlier this year at Infineon Raceway to become the first non-American to capture a Cup event since 1974. Franchitti will become the first European driver in NASCAR history to drive a full schedule.
"The biggest motor racing series in America is this," Montoya said. "If you want to make it big, this is where you want to be."
Franchitti will begin his baptism into stock cars this weekend with the ARCA race at Talladega, just as Montoya did last year. Franchitti is expected to graduate to a Busch Series event and then a Cup event before the end of the season.
Ganassi Racing already is seeing the benefits of having high-profile international stars, with sponsors from Russia, Germany and Spain bidding for a spot on Franchitti's car.
"This gives us a platform of being a global property," said Ganassi president Steve Lauletta. "It opens the door for us to a much wider path of potential sponsors, potential opportunities and doing some things other teams can't.
"The leagues that are trying to be the first sport to globalize from the U.S. to the outside, this gives us the chance to be the poster child for NASCAR and motorsports."
Lauletta said NASCAR, which was born on good ol' Southern boys and American products, needed to take this step to grow.
"The ability for us to not bang our heads on the list that everybody is talking about, this gives us a chance to tell a story," he said. "From the indications so far, that's going to be a pretty interesting thing for us to talk about."
Lauletta said it will be much easier to sell a driver with Franchitti's reputation than it was to sell an up-and-coming driver like David Stremme, the driver Franchitti will replace.
"As people are trying to align themselves with powerful brands, a brand like Dario Franchitti or Juan Pablo Montoya versus a young guy coming up in the sport that the hard-core or casual fan doesn't know, it's a different conversation we have," he said.
Franchitti's star power goes beyond what he can do behind the wheel. He's also married to film star Ashley Judd.
"We have been watching a lot of [Cup] racing recently," Franchitti said. "Ashley turned to me and said, 'Now that you're doing this next year, do we have to watch it on TV quite so much?'"
So did the room full of reporters.
While he speaks with an accent not familiar to many stock car fans who grew up on Richard Petty and Cale Yarborough, he has the same sort of appeal that has made Montoya an instant star in NASCAR's premier series.
"It's a big thing for me to come into NASCAR; it's a big step for me," said Franchitti, who lives in Nashville, Tenn., with his famous wife. "It's a big change from everything I've done before. Hopefully, we're going to help grow the sport internationally, as well.
"But right now my focus is to get in the car and just be competitive."
Franchitti has been successful at every level in the past. He and Montoya were deadlocked for the CART points title in 1999, but Franchitti lost on a tiebreaker.
In 180 starts between the IRL and CART, he has 18 wins, 63 top-5s and 95 top-10s.
Montoya believes his new teammate will make a smooth transition, noting that Franchitti has spent the past six years driving on ovals while he was on road courses.
He hopes one day in the near future the two will be competing in the Chase for the Nextel Cup with other international drivers.
Franchitti just wants to get through his first ARCA race, saying that the move to NASCAR will be the "toughest challenge of his career."
It's not what he envisioned eight years ago, for sure.
"It's just amazing," Franchitti said, "the way things have turned out and the direction that NASCAR has taken with drivers coming from further [around] the world."
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.