Allen was named by Grove Racing as a replacement for Stanaway in this afternoon’s race after the Kiwi was sidelined with concussion.

However that plan has now changed with Allen not allowed to compete.

Speedcafe understands that the direction came from Eggleston Motorsport, who is looking to seal a second Super2 title with Allen this weekend.

If Allen had raced in the main game he wouldn’t have been able to race in Super2 tomorrow.

Dale Wood, who partnered Stanaway at Grove Racing at the enduros, will race the #26 Mustang instead, starting the race from pit lane.

Stephen Grove explained to Speedcafe that all rival Super2 teams would have needed to sign off for Allen to compete in both classes.

“The way the rules are written the stewards had nowhere to go,” said Grove, who had moments earlier been competing in the same Carrera Cup support race as Wood.

“They can’t do anything other than we needed to get all the Super2 teams to approve it, which we didn’t have time to do.

“The only way around it was for them all to support it, but we can’t contact them all within 10 minutes, so we had to make a call and Dale’s our man.”

It’s understood that Groves wanted to run Allen and then seek permission from the Super2 teams for the driver to compete in Super2 tomorrow.

However, Eggleston Motorsport insisted that the sign-off be achieved before Allen drove the Grove car, which was not possible in the timeframe.

Jack Perkins managed to achieve sign-off from all rival teams to compete in both classes at Sandown, but he had weeks in which to gather the signatures.

Allen is somewhat of a long shot for the Super2 title heading into tomorrow’s decider after a mistake in Race 1 meant he finished seventh.

That’s left him 84 points behind Zach Bates. Eggleston Motorsport is, however, right in the fight for the Super2 teams’ title.

Grove meanwhile said it’s unclear whether Stanaway will be OK to resume driving duties on Sunday.

Stanaway – who crashed in qualifying on Friday – had two off-track excursions in Saturday morning practice before reporting post-session that he felt unwell.

“He reported he wasn’t feeling very well and when they asked some questions, it indicated potentially some concussion, or something wasn’t right,” Grove explained.

“Then we got the medical team down here straight away, Dr Carl [Le], and they came and had a look and then made the decision. We don’t think he’s right.

“We don’t know,” Grove added of Sunday. “We need to send him off to get an external check and then the medical people will make that decision.”