The 1969 HT Monaro was credited with launching the Holden Dealer Team's racing dominance in the 70s and 80s.

The car was the first prepared by motorsport legend Harry Firth and debuted at the 1969 Sandown 300.

The car crashed out in a firey crash at the 45-minute mark but it was vital to the team's later success.

Lessons leaned helped Colin Bond and Tony Roberts claiming victory at Bathurst the same year. Des West and rookie Peter Brock finishing third.

Rod Coulson fell in love with the car when he saw it at a 1998 event marking Holden's 50^th year.

He bought it three weeks later.

"I've always been a bit of a car nut. I thought it was really important to get from a historical perspective," he said.

Mr Coulson brought it to Bendigo where he did a sympathetic restoration.

"The car had been stored on dirt for many, many years. I didn't know when I bought it - I certainly learnt as I went along - that moisture bleeds up through the tyres if a car sits there for a long time," he said.

Mr Coulson replated every nut and bolt on the car and gave it a new paint job.

It took him seven years to complete that project.

"It wasn't a huge job by any stretch of the imagination. It was just time consuming," he said.

Mr Coulson ended up selling the car in 2017 through Lloyds Auctions, the same group that will auction the car this Saturday.

Lloyds' chief operations officer Lee Hames said the car's history could help it double the previous record for a Holden vehicle sold at auction.

"The inquiry on this car is massive from all over the country, many people are even saying that it will reach seven figures," he said.

"While we're seeing rare classic cars like Holden Toranas and GT Falcons selling for hundreds of thousands, none have the colourful backstory or cultural significance of this Monaro, which is what makes it so rare and special."

Mr Hames said online bidding is now available.

Click here for more details.