This has been in the works for some time. In fact, it sprouted from a short conversation about Cup engines and Busch races.

It grew after Mark Martin signed with Ginn Racing last fall for a part-time Cup schedule this season. Hendrick Motorsports provides engines for Ginn, and that peaked Martin's interest.

And Rick Hendrick's, too.

"When I heard that he was going over to Ginn Racing and he wanted to talk to us about our support and the engine program, we just started talking," Hendrick said, "and he said, 'Hey, I'd like to drive one of your Busch cars one day.' And it just kind of started."

By the Numbers

No other car has led more than the No. 5 this year. And at Darlington, no other driver has won more than Mark Martin.

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"Start" is such a loose term for Martin. He started his NASCAR career running five Cup races for Bud Reeder in 1981. He started his Busch career with one race in 1982 driving for Ed Whitaker. Since then he's started 921 races in NASCAR's top three series for 15 different owners, including himself.

No. 16 comes Friday night at Darlington Raceway when he sits a Hendrick-owned Chevrolet for the first time for the Diamond Hill Plywood 200 (8 p.m. ET, ESPN2).

"It's exciting," Hendrick said. "He's such an icon. And I think we'll learn something. I think we'll learn a lot from Mark and his input."

Hendrick learning from Martin? When it comes to wheeling a Busch car at Darlington -- or anywhere for that matter -- it's true.

Martin's 47 career Busch victories are more than any other driver in series history. His eight victories at Darlington are twice as many as anybody else. His last four trips to the South Carolina track have resulted in three consecutive victories and a fourth-place finish.

But it's Martin who insists he's the student, not the teacher.

"The thrill for me is to be able to drive for Rick Hendrick, and to be able to say that I did that before my career ends as a driver is really special," the veteran said. "To have them with their enthusiasm and a chance to work with more really brilliant people that I can maybe learn something from, this is the greatest time in my life.

"I see how fast the car is. I see they don't need my input. If they did, I would've gotten involved sooner, but the program is so strong they really don't need my input from a technical side."

Kyle Busch is competing on a part-time schedule, having run nine of the 11 races this season. He's still sixth in the points and had the car up front for a series-high 532 laps led. Busch is sitting out Friday night's race and handing the wheel to Martin, who admits he's somewhat overwhelmed with the situation.

"That No. 5 means something to me," said Martin, who spent the majority of his career driving a car with 6 on the door. "I remember the No. 5 when it was first getting started -- when it was All-Star Racing on the side and Rick Hendrick was a car dealer getting into NASCAR. This is stuff that's history. And the older you get the more history means to you."

That was 1984, when Geoffrey Bodine drove the 5 car for Hendrick in the Cup Series. He scored three victories that season.

Since then only three drivers have wheeled the 5 car full time in the Cup Series: Ricky Rudd, Terry Labonte and now Busch.

The 5 car's history is more personal in the Busch Series. It debuted under the team flag in 2002 with Hendrick's son Ricky at the helm. The next year Brian Vickers drove it to the series championship. Since then it's primarily been Busch's ride. And he hasn't tarnished the record.

"The way this car has run this year with Kyle in it, if I can get in there and not do something stupid, and do a good job of relaying information and integrating and working with the team, then we should have a shot at it," Martin said of the possibility of ending the night with a victory.

To achieve that, Hendrick said, doesn't necessarily mean the team will be lifting a trophy.

"I kind of compare it to having Darrell Waltrip win the Daytona 500 in our car," Hendrick said. "When I look back at the end of the day and we look at the wins we have and the people that have been part of it, I think it's going to be really neat to have Mark's name on that list."