Autosport understands that Supercars is considering mapping changes for both the Chevrolet and Ford V8 units ahead of the high-speed Symmons Plains circuit this weekend.
The Ford change is expected to be the more major of the two given the suspicion from the Blue Oval that its engine still lacks mid-range torque delivery compared to the Chevrolet.
That could potentially be highly visible at Symmons Plains given its two high-speed, full-throttle sections in and out of the hairpin.
Sources within the Ford camp have suggested that this will be the latest, but unlikely the final, mapping change relating to parity.
It's expected that tweaking will continue into the foreseeable future, and likely until a proposed transient dyno testing programme is complete.
Supercars is known to be investigating the use of a transient dyno based in Melbourne to better understand the nature of the power and torque delivery of the 5.4-litre quad cam Ford compared to the 5.7-litre Chevrolet.
A number of metrics already in play suggest there is parity, or very close to it, between the motors.
The Accumulated Engine Power figure, where horsepower is measured at 200 rpm increments within a specified rev range, is thought to be equal – something that was sufficient to denote parity when both units were five-litre pushrod designs.
Lap times have also favoured an argument of parity, particularly based on figures distributed following the recent Perth SuperSprint.
Source: Autosport