There, Walkinshaw Andretti United, Kelly Grove Racing, Tickford Racing, and the Blanchard Racing Team all ran cars with windscreen surnames present.
"In testing, what we wanted to do was make the car number more visible and clearly call out the driver that's in the car," Supercars CEO Sean Seamer told select media on Thursday.
"It's actually a request that's come form our broadcast partners and some views, so they can more easily identify the specific car and driver.
"As the cars evolve the numbers get smaller and smaller as we've got less real estate to put them on."
The 2021 Repco Supercars Championship will commence at the Repco Mt Panorama 500. Tickets are on sale now.