Staying on the same sort of theme in the post above, here is a short list of great race car drivers that couldn't quite get the hang of NASCAR's top tier of competition.
Juan Pablo Montoya
Montoya came to NASCAR with an extremely impressive open wheel resume to back him up. Won the Indianapolis 500 in his first attempt, and won races for Williams and McLaren in Formula 1, some of the best non - red car teams at the time.
Montoya drove for Ganassi his entire NASCAR career. He did manage to grab two wins, but they were both at road courses. And NASCAR's schedule is currently 94% ovals. Aside from almost winning the Brickyard 400 (which I believe was mentioned in this thread already), and a few other small flashes of brilliance, Montoya was usually around the upper - mid pack, taking no wins on any oval he competed on. He made the Chase
(the worst championship structure known to man, story for another time, though...) once in 2009 where he finished 8th, but he finished around 20th in points in the rest of his career. Although he had some good moments, Montoya was never really a big threat for race wins for most of the season, nor for the championship.
In 2014, Montoya returned to IndyCar with Team Penske. In 2015, he won his second Indy 500, and almost won the title. His career continues into 2016.
Marcos Ambrose
Around the same time Montoya entered the championship, Marcos Ambrose came up from Australia to compete in the Sprint Cup. A 2 - time champion of the V8 Supercar Championship, Australia's premier touring car series.
Like Montoya, Ambrose was an absolute ace on the road courses. After all, a Sprint Cup car has a lot in common with a V8 Supercar. And also like Montoya, he only managed to grab two career Sprint Cup wins. But they came at the same track: Watkins Glen. He came very close to winning a race at Somona, but made a mistake while trying to save fuel, completely stalling the car under caution, losing the lead, and ultimately the race. Outside of that, he had no oval wins in his entire NASCAR career. Ambrose had 0 Chase appearances, with a highest points position of 18th, which he achieved twice (2009 & 2012).
After 6 full Sprint Cup seasons, Ambrose returned to Australia with intentions of coming back to the V8 Supercar Championship in 2015. Unfortunately, while the return was highly anticipated, the start of his season was pretty dismal, qualifying at the back nearly every time, and earning a highest finish of 12th. Shortly after the start of the season, Ambrose opted to step out of the car and hand it over to Scott Pye for the remainder of the year, only returning for the endurance races where two drivers are required. It appears as though Ambrose won't be a full time driver in 2016, either.
Dario Franchitti
This happened so quickly, I'm not even sure people remember it even happened. But it did. For 13 races...
Personally, I also love how the livery on his car had a car on it.
Franchitti entered NASCAR hot off an IndyCar title and an Indy 500 win. He drove the #40 Dodge for Ganassi in 2008, but the #40 team was ultimately shut down in July of that year. To make matters worse, Dario injured his ankle in an Xfinity (then Nationwide) series crash early in the year, so he didn't even drive the car the entire time it was in competition, missing 5 races. When he
was in the car, Franchitti managed a highest finishing position of 22nd. With an average finish of 34th. He even failed to qualify more than once.
In 2009, Dario joined Ganassi's IndyCar team, and pretty much returned to his winning form. He would go on to gain two more Indy 500 wins, and 3 straight IndyCar titles. But unfortunately, an airborne wreck at Houston would see Dario retire from racing. He now commentates on Formula E.
Sam Hornish Jr.
Yet another great open wheel driver taking a stab at NASCAR's premier series. 2006 Indy 500 winner, and a 3 - time IndyCar champion.
Being a Penske IndyCar driver, it was a natural move to Penske's NASCAR division, which he made in 2008. However, Hornish was not met with the same success he saw in an IndyCar. His Sprint Cup career is mired with plenty of 20th and 30th place finishes, with only a couple of top 10 blips.
In 2011, after Mobil 1 pulled their sponsorship from the Penske team (to move to Stewart - Haas), Hornish was moved to Penske's Xfinity team. And in an Xfinity car, Sam wasn't too bad at all, with a few wins, quite a number of top 5 finishes, and a second place championship run.
Hornish returned to Sprint Cup racing with Richard Petty Motorsports in 2015 to replace Ambrose. And a lot of people (yours truly included) thought this was a great move for both Hornish and Petty, based on his past performances in NASCAR's lower tiers. Although expectations were high, all Hornish really managed to do was obtain his highest ever year end points finish: 26th.
In 2016, Hornish was replaced with Brian Scott, with the car number changing from #9 to #44. It appears as though Hornish has not returned to racing in 2016, but has become a TV personality within the last few years.
I'm sure there are more, but this post must finish at some point...