It was a little over a month ago when seven-time NASCAR Cup Series champion-turned-IndyCar rookie Jimmie Johnson and four-time IndyCar champion and one-time NASCAR Cup Series rookie Dario Franchitti sat in Johnson’s Charlotte home and talked racing. OK, they were trying to talk racing. But they were quickly interrupted by Chandra Johnson, wife of a NASCAR legend-turned-IndyCar rookie.

So what did Mrs. Johnson ask Mr. Franchitti?

“‘Is my husband going to make a fool out of himself?'” Johnson recalled Thursday morning, chuckling as he prepared to jet south to Birmingham’s Barber Motorsport Park for Sunday’s Honda Indy Grand Prix of Alabama, his first open-wheel start and first of 13 planned road and street course events.

And what did Mr. Franchitti tell Mrs. Johnson?

“He never hesitated. He said to her, ‘No, he is not. You have nothing to worry about,'” Johnson said. “That’s the good news, that Dario isn’t worried. The bad news is that I don’t feel nearly as confident about it as he does.”

It’s not that the man lacks for confidence. He is, after all, the winner of 83 Cup Series races, including a pair of Daytona 500s. He just wishes he had a little more seat time in the lighter, faster, more nimble IndyCars. OK, a lot more seat time. Moving from a racing life lived behind the wheel of a 3,400-pound stock car and into the cockpit of a 1,600-pound open-wheel machine is like going from piloting an Airbus to an F-22 fighter jet. NASCAR is about momentum, how one throws that weight around and how it throws them around, building speed one lap after the other. IndyCar is point-the-nose-and-go, with everything and anything happening instantly.

Last July, after Day 1 of his oft-COVID-delayed first test session, Johnson responded to a “How was it?” text with a GIF from the cockpit of the Millennium Falcon as it made it the jump to light speed.

“It is so exciting, but it is also so challenging. I have had to literally rethink everything I know about driving a race car. In a stock car, speed is all about how you attack the exit of a turn. In an IndyCar, it’s about how you attack turn entries. There is so much acceleration into the turn. That’s new.”

There is so much that’s new it’s hard to keep track. Everything from race starts and pit stops, to terminology (when the rear end of the car loses grip and goes sideways, that’s no longer “loose,” it’s “oversteer”) and tire spin. It’s the latter that’s been giving him fits, struggling a bit to understand braking and acceleration points with the bigger tires on a lighter car. He’s really wrestled with getting his Firestones up to the right temperature and air pressures, accidentally spinning and burning up those tires prematurely. With strict tire limits, there’s no rubber to be wasted.

“The biggest worry I have is making a dumb mistake, something that stems from inexperience,” Johnson said. “Using up tires or botching a pit stop, or even just getting in the way when I don’t mean to. We were limited to only five tests and the last one of those was a while ago, early March. I got probably 150 laps in during each test, so do that math and it’s not a lot of laps.”

To make up for that lack of seat time, Johnson has traveled to Speedway, Indiana, to strap himself into race car manufacturer Dallara’s sci-fi film-worthy 360-degree simulator. But pandemic travel restrictions kept engineers from gathering and uploading updated 2020 data. It’s still set up to 2019 race specs. So while the sim time gave Johnson a great handle on the racetracks, it only provided a partial feel for his 2021 ride. To fill in those gaps, he has worn out the video and data servers of his new team, Chip Ganassi Racing, watching every angle of every 2020 race lap and pit stop over and over, as well as everything gathered during his five tests.

Right now, those downloads have been limited to the road and street courses, the 13 events he’s running this season, sitting out the four ovals. That means no Indy 500. For now. When asked to gauge the possibility he might change his mind next month, he rated the chance as “a sliver.”

The other data banks he’s mined are the human ones, especially Franchitti and teammate Scott Dixon, who also happens to be the six-time and reigning IndyCar champ, aka the Jimmie Johnson of open-wheel racing. “Yeah, I have leaned on Dixon some, but when I was so many seconds off his pace in the beginning, I tried not to bother him. As we inched closer, I feel like I’m a little more worthy to ask a few more questions.”

Dixon scoffs at such remarks, echoing the universal praise being heaped upon his 45-year-old rookie teammate, coming from every corner of the IndyCar paddock. “He has already covered so much ground with very limited laps. You saw immediately how competitive he is. The intensity is just insane. Everyone knows what amazing shape he is always in physically, but he has even changed how he trains to prepare for the different feel of these cars, for the g-force loads. He is covering all his bases. That’s how you win seven championships. This is going to be so big for IndyCar to have him with us.”

How big? No matter what Johnson’s results might be, he will make motorsports history simply by showing up in Birmingham this weekend. While there has been a long list of IndyCar superstars to jump into NASCAR with some success — A.J. Foyt, Mario Andretti, Parnelli Jones, Dan Gurney and Johnny Rutherford all won Cup Series races — that has rarely happened in reverse. A few NASCAR stars, including Indy 500 Rookies of the Year Donnie Allison (1970) and Kurt Busch (2014), have shown flashes of potential, but no NASCAR driver has ever won an IndyCar event and only one crossed over to run the full open-wheel schedule, a fact so little known that not even a fellow legend knew about it until he was told on Thursday.

“Wait … Cale Yarborough ran a full IndyCar schedule?!” Johnson replied when told the three-time Cup Series champ did indeed run the USAC Championship Trail calendar in 1971. He also came the closest to winning an open-wheel race, leading with less than 10 laps remaining at Ontario Motor Speedway. A decade later, after Yarborough had won three consecutive Cups and had 83 wins, a kid who grew up not far from Ontario made his family drive out of their way to find a Hardee’s hamburger joint so he could buy a die cast toy of Yarborough’s famous No. 28 Hardee’s-sponsored ride.

That kid’s name was Jimmie Johnson, and he recalled that story for Yarborough in 2008 after he tied that record of three straight championships. Now they also sit together with 83 Cup Series victories, sixth on NASCAR’s all-time wins list.

“That’s the part of this experience that I get the most excited about, following in the footsteps of the racers who were my heroes,” Johnson added, his voice beaming through the phone line. “When we were kids we’d say, ‘Who do you think you are, Parnelli Jones?’ We said that because he raced everything everywhere. Parnelli, A.J. Foyt, the guys who have run the Charlotte/Indy Memorial Day weekend double duty. Being able to cross over like that, like I have the opportunity to do now, this is as old school as it gets. I’m ready to go, man.”