Richards and Murphy are paired in the lead Firepower Tasman Holden VE Commodore.
Murphy is a two-time winner of the traditional Bathurst warm-up, having won back-to-back with Craig Lowndes in 1996/97, while Richards finished on the podium in 2005, and went close to winning the race two years prior, challenging Mark Skaife for honours over the closing laps.
"Sandown and Bathurst are totally different races compared to the sprint rounds and there's always a fair bit of luck involved, and it's not necessarily the fastest car that wins all the time," said Richards.
"We've got a strong driver line-up and our Tasman Motorsport Commodore has proven itself to be reliable.
"Murph's won this race twice before, and I've done well here, so I'd like to think we're a realistic chance of winning."
Richards said the weekend's forecast of late showers could be a factor in the race's outcome.
"It wouldn't be Sandown without Mother Nature throwing her traditional curveball," he said.
"The conditions can change quickly, but we're not too concerned, we've had good speed all year and Oran Park showed our wet setup was strong.
"If it does rain though, it will close things up and make life interesting."
For Murphy, the arrival of the annual endurances races has been eagerly anticipated.
"Sandown and Bathurst are races that I've had good success at and always enjoyed, so I've been looking forward to them," said Murphy.
"Strategy comes into play a lot more during these events and the competition becomes more open. There are more opportunities to stay closer to the front and more chances of Safety Cars.
"They're really a bit of a different ball game and if we've been able to make just a small gain from Oran Park then we'll be in the mix."
Fujitsu V8 Development Series standout, Jay Verdnik m akes his main game and Sandown debut alongside experienced campaigner Mark Noske in the second Firepower Tasman Commodore.
The 21-year-old Verdnik has never been to the Melbourne circuit before, but is not too concerned.
"I know it's not quite exact, but I've done plenty of laps on the Playstation and it's given me some idea about what to expect!" said Verdnik.
"I'm sure there'll be nerves, but at the moment I'm feeling pretty comfortable about it all. Tasman has been terrific, they've given me plenty of laps in the car during testing and Mark has been a great help."
For Noske, who returns to the team for a second straight endurance campaign, a strong finish is the goal.
"The main thing for us is to not get carried away; early on we need to give Jay as many laps as we can, while our goal for the race is to stay out of trouble, keep the car straight and stay on the lead lap," said Noske.
"Time and again, it's been proven if you can do that you've got the chance to finish in the top 10 and that would be a terrific result."
Murphy and Richards will drive the #51 Firepower/Tasman Motorsport Holden VE Commodore and Noske and Verdnik will carry the #3 on their car.
Practice for this weekend's Just Car Insurance Sandown 500 begins Friday afternoon, with a second practice session and qualifying scheduled for Saturday. Sunday's 161-lap race begins at 1.30pm.