There is concern among the Ford camp about how Sunday’s Penrite Oil Sandown 500 will play out after Chevrolet Camaros dominated Friday practice.

Mustangs were no higher than fourth on the timesheet in any of the three sessions, with the latter of those ending in an all-Camaro top eight.

Just one Mustang finished in the top nine in Practice 1 while the figure was one in 10 in the second hit-out of the day, which was for co-drivers only.

One Ford figure claimed that they are staring at a 24-second disadvantage over the course of the 161-lap race on straight-line deficit alone, based on data from Practice 1.

Penrite Racing Team Principal David Cauchi was another who had worries at the end of Practice 3, when the top Mustang was almost half a second (0.4567s) away from the fastest lap of the session.

“Look, it’s looking like it’s in the range of almost three tenths if you correct it to a 60-second lap,” he told Speedcafe.

“I think it was .285 in Practice 3, so yeah, it doesn’t look very good for us for the weekend, but Supercars say we have parity, so there’s not much more that we can do.”

The 60-second lap correction is of significance because that metric forms the basis of the parity trigger, the activation of which led to an official parity review following the Hidden Valley event and a new aerodynamic package next time out at Townsville.

Furthermore, while precise details of the trigger are a closely-guarded secret, a one tenth per lap discrepancy taken over a sample of cars of each model, over five consecutive races or five of eight Championship races, is the threshold for a review.

Straight-line speed is an obvious potential source of disparity this time around, given the nature of the Sandown layout and its two ‘drag strips’, but questions are also being raised about the corner-dominated microsectors.

“In Practice 1, it was it was predominately in the straight-line sectors,” said Cauchi.

“I haven’t looked in detail at Practice 3 yet but I don’t think it’ll just be straight-line, unfortunately. I think it’ll be a bit more than that.”

At the Shell V-Power Racing Team, which homologates the Mustang, CEO David Noble is also pessimistic.

“I think we’ve got a challenge in front of us to try to make up as much ground as what it looks like,” he told Speedcafe.

“So, it’s probably the disappointing thing; you come out of The Bend with maybe some hope and then it just doesn’t look like it’s there again.

“I’m hoping it doesn’t pan out that way but, by the end of the weekend, if it is heading in the direction that it is heading, then we’re going to have to have some serious discussions again with Supercars.”

Practice 4, the final session before qualifying, starts tomorrow at 10:45 local time/AEST.