Marcos Ambrose took a break from his arduous NASCAR Sprint Cup program to test a Grand-Am prototype sports car for the first time in his career at Virginia International Raceway this week.

Ambrose and fellow Sprint Cup regular Carl Edwards got a feel for the speedy #77 McDonald's Dallara-Ford prototype fielded by Doran Racing.

"That was the first time I have driven one of these cars and I have to say that I was pleasantly surprised by what a terrific little race car it is," said Ambrose.

"You can really drive it and it responds to being muscled a bit.

"We had a really enjoyable day and we made some solid progress in a short amount of time.

"Carl was great to work with and I think we both really had a good time together today.

"Both Carl and I got down to some pretty respectable times by the end of the day."

While Ambrose and his PR minders are commenting little on the significance of the test, the American motor sporting media seems sure that Ambrose and Edwards will make their Grand-Am Rolex Sports Car Series debuts on August 29 in Montreal.

There had been earlier speculation that Ambrose would join Jimmie Johnson in a Ganassi Grand Am car but that one went nowhere...

The Ambrose-Edwards combo has excellent road racing credentials with each driver scoring recent podiums at Watkins Glen.

Team owner Kevin Doran's #77 Daytona Prototype has competed in all nine rounds of the 2009 Grand-Am Rolex Series, with a best finish of fifth at Virginia International Raceway in April, with Memo Gidley and Brad Jaeger at the wheel.

If Ambrose does race the Grand Am car on August 29, Australians will get to see it - the One HD sports channel telecasts the series, hosted by Aussie Leigh Diffey.

Coming up this weekend, though, for Ambrose is a return visit to the 24-30 degree banked Bristol Speedway half miler where rubbing fenders is obligatory.

In his first Sprint Cup start at 'Thunder Valley' in March, Ambrose looked set for a fourth-placed finish after a strong run.

But he dropped to 10th place in the late stages as he nursed home his #47 JTG Daugherty Racing entry, which developed engine problems.

The Bristol night race always has a special place in Ambrose's heart, as it was at this race in 2003 that the Australian V8 supercar champ visited his first NASCAR event, planting a seed that saw him make the switch to NASCAR in 2006.

"I've been looking forward to the Bristol night race all year," said Ambrose.

"We ran really well at Bristol earlier in the year. We had a great run and ran a lot of laps in the top five and ended up having to nurse the car home with a motor problem.

"We still scored 10th and it was a great result for our team. Bristol is such a tough place, if you can run well there you really feel satisfied.

"We have put [last week's crap outing at] Michigan behind us. Bristol is a track that's very demanding and is pretty intimidating for a driver, but it's a track I always enjoy going to, ever since I was a spectator at the race there back in 2003."