Nissan’s hopes of a competitive return to the Bathurst 1000 have been boosted by the last-minute introduction of a revised cylinder head for its four Altimas.

The team had been working on the latest iteration for some months, with a major push made in recent weeks to ensure it could be implemented for The Great Race.

The need to have the upgrade run on V8 Supercars’ dyno in Queensland and approved by the category ensured that two of the team’s cars were dispatched for Bathurst earlier this week without engines aboard.

Both were installed at the circuit on Wednesday; one of which had travelled to Bathurst directly from Queensland via a support race team transporter.

Team co-owner and driver Todd Kelly believes that the economy-focussed changes will prove the difference between needing to do seven or eight stops in a fully green race.

Seven stops have been made compulsory for all cars at Bathurst this year in order to assist the competitiveness of the four-valve engined Nissans and Mercedes AMGs.

“If it (the revised head) can get us a good gain in economy we might be able to go from 19 lap stints to 21 laps, which will be huge for opening up our strategy and lessening fuel (fill) time,” Kelly told Speedcafe.com.

“Based off the dyno it looks like it’ll be quite good but we won’t know exactly how good until we put it on track.

“The guys have worked so hard to get everything done for the weekend; they really did only just make it.”

Kelly trialled some initial elements of the revisions on his own car at Sandown, where the #7 Jack Daniel’s entry proved the most competitive Altima in qualifying and the race.

The changes are the latest product of the team’s engine program in Melbourne, which remains split between its factory in Braeside and its dynos in Moorabbin.

The squad will ship one of its VK56DE’s to Nismo’s headquarters in Japan in the weeks following Bathurst in order to further boost development.

With Nismo’s involvement in the project to date has consisted of advice and the loan of existing Nismo parts for assessment in Melbourne, the engine’s shipment marks the first time that the Japanese will work directly on the V8 Supercars program.

Although Kelly is expecting gains from Nismo to flow as early as the final events of this season, the team will soon need to make make a call on whether a larger change to the cylinder head is needed for 2014.

Like Erebus, Nissan remains uncertain as to whether or not V8 Supercars will make a regulation change, such as the upping of the compression ratio for four-valve engines, in order to save the new marques considerable development costs.

“Nismo will give us some good gains, they’ve got extremely good test equipment and hopefully there’ll be some improvements in combustion and areas like that which will help,” said Kelly.

“But I’m not having my fingers crossed that they’ll find 25 horsepower for us, (because) I’m confident that we’ve now absolutely maximised the cylinder head as it is in its production form.

“We can’t go any bigger in the valve size and the port because of the constraints that we’ve got in the road car based cylinder head. To make the power that we need to, we’re going to have to modify the casting of the cylinder head to achieve that.

“It’s coming to the point where we need to know if we’re either going to get a dispensation to overcome the issue or try and go to the expense and the time to modify tooling (at the Nissan engine plant in the United States) to do another run of cylinder heads.”

In the meantime, Kelly has marked out the goal of a 100 percent finishing record for his cars this weekend, with sneaking into the top 10 at the end of Sunday afternoon a bonus.

“We’ve got a lot of good information from the season so far to know what to expect here and we’re quite realistic on where we are,” he said

“If we were 8km/h off of a 260km top speed at Sandown, then if 295km/h is the speed at Bathurst, we’re not going to be going any better.

“Now that we’re here we’re locked into whatever straightline speed and fuel economy we have, so we’ve got to focus on getting a good set-up and doing what we can.

“My goal is, after 21 years away for Nissan, I want to have four cars finish. If things go our way we could get a few into the top 10. I think that’s a realistic aim.”