Ryan Thompson's father, Richard, received unexpected news that he needed a major surgical procedure at Canberra Hospital this week so every hour in the show lead-up had been precious.

"Dad had done hundred and hundreds of hours work on the car and as we got closer to the event and still had a lot to do, we then got told he was going in for surgery on January 9," Ryan said.

"At first we thought we should just hold off until next year but then we talked about it a bit more and realised it would be a shame to have got this far with it and not get to the show as we had planned all along."

The father and son team took on the HQ Holden ute three years ago as their Summernats project after selling their ski boat which had been sitting idle as a result of the shutdown in the local Molonglo River ski area.

The family loved to go water-skiing locally but despite repeated queries to the ACT Government, they couldn't get a straight answer about the future of water-skiing on the river.

So out went the ski boat and in came the HQ.

"Dad's so great at tinkering with things and making stuff and I thought a show car would be a great project to work on together but the car we bought as our platform turned out to be absolutely terrible."

Swathes of rust holes and body filler had been artfully concealed by the car's previous owner, requiring large-scale replacement of body panels and a complete back-to-bare-metal strip-down.

In a farm shed off Wallaroo Road, the HQ project slowly gathered momentum.

Richard, a retired public servant, described it as a much bigger project than they had ever anticipated with the car returned to its bare chassis and rebuilt from the ground up, with every part of the reconstructed body hand-filed and inspected.

When it came off the tilt-trailer last week for Summernats scrutineering, the reborn, supercharged V8 Holden show car in its fresh orange paintwork had travelled less than 1 kilometre.

So it came as no real surprise that when the ute went in for judging, teething problems soon emerged.

"The engine developed a fuel delivery problem; it just wouldn't run properly," Ryan said.

"It made the finals of the street and elite categories but we couldn't put it out on public show the way it was running so we packed it up and brought it home straight after judging."

Despite the rushed preparation, Ryan said it was a good experience to get the car into the show and once his father fully recovers from surgery, they will go back into the shed and work on the car again together.

"You look at what other guys at the show have done with their cars and realise just how high the bar is set. But we'll be back next year and give it a huge go."