Top speeds are set to become a talking point at this year’s Repco Bathurst 1000 with a change to the prescribed drop gear ratio.

Mount Panorama already featured the tallest of any of the mandated ratios, which are set by Supercars and apply equally to the Ford and Chevrolet (previously Holden) at any given track, with the 2023 Operations Manual stipulating a 0.931.

However, that has been made even taller per the Supplementary Regulations for this year’s Great Race, at 0.909.

It raises the question as to whether or not the Gen3 Supercars will crack the 300km/h figure at the end of Conrod Straight.

A taller drop gear means a higher top speed, all other things being equal, but that much could be academic because of the trade-off of slower acceleration.

Indeed, the 300km/h figure remained elusive the last time Supercars mandated a taller drop gear ratio at Bathurst, back in 2015.

Supercars made that change then, in the third year of Car of the Future, in order to reduce the time which engines spent on the rev limiter before turning into Conrod Straight, and hence enhance reliability.

COTF, however, represented carryover in so much that the Ford Falcons and Holden Commodores of the day retained their 5.0-litre pushrod engines from the Project Blueprint era, whereas the new-for-2023 Gen3 Mustang is powered by a Coyote-derived 5.4-litre double overhead cam unit and the Camaro by the 5.7-litre pushrod LTR.

Drop gears have already been made a step taller for multiple events so far, at Symmons Plains and Sandown, both of which have long back ‘straights’.

Sandown also has a relatively long pit straight while Mount Panorama boasts the 1.111km Mountain Straight and 1.916km Conrod Straight.

Teams will still have to take the 0.931 drop gear and a 1.000 as the official back-up ratios for the Bathurst 1000.

The compulsory pit stop counts for the Sandown 500 and Bathurst 1000 are yet to be confirmed, but a front pad change has been mandated at the latter at some point from the start of Lap 55 to the end of Lap 120.

That marks something of a change from last year, when the compulsory brake service was a rotor change rather than pads only.

Pre-enduro testing begins this Monday, with the Sandown 500 on September 15-17 and the Bathurst 1000 on October 5-8.