Just 0.0374s separated Shane van Gisbergen and Will Davison at the end of Practice 2 at the Thrifty Newcastle 500.
The reigning champion's 1:11.7555s was marginally better than Ford rival Davison's 1:11.7929s after 45 minutes of running.
Van Gisbergen, Davison, Broc Feeney, Chaz Mostert and Andre Heimgartner all dipped below the Practice 1 benchmark.
Click here for Practice 2 results
That was set by Brad Jones Racing driver Heimgartner, whose earlier 1:11.9958s would have good enough for sixth in Practice 2.
The top 19 drivers were covered by just 0.9916s in Practice 2, with the top 10 featuring five Camaros and five Mustangs.
Van Gisbergen didn’t have it all his own way in the session — he ran off at Turn 2, and also had a wobble at Turn 11.
Practice 2 featured pit stop practice, with teams bedding in their new systems.
Notably, the new Gen3 cars have smaller wheel nuts, a single-nozzle fuel coupling and a front-located air spike.
Heimgartner led the early running with a 1:11.9836s in his #8 R&J Batteries Camaro.
Aboard the #17 Shell V-Power Ford, Davison jumped to the top with a 1:11.7929s, with Feeney jumping to second with a 1:11.8722s.
Through his various close calls, van Gisbergen — who won a record 21 races last year — jumped to the top with a 1:11.7555s.
The #97 Red Bull Ampol Camaro also ran long at Turn 1 in the final minutes, but van Gisbergen remained at the top by the chequered flag.
Up and down pit lane, teams continued to learn their new pit stop processes, with some squads finding trouble along the way.
Notably, Mostert was delayed due to a a mishap applying the wheel to the hot spindle.
The two-time Bathurst winner — in his first event in a Ford since Newcastle 2019 — later caught traffic on his final flyer.
Scott Pye ended up sixth in his #20 Hino Camaro ahead of Team 18 teammate Mark Winterbottom.
Anton De Pasquale made it two Shell V-Power Racing Team Fords in the top eight, with Cam Waters and James Courtney rounding out the top 10.
Todd Hazelwood was 18th, having nudged his former team car now driven by Cameron Hill at Turn 11.
Hill, one of three rookies in the field, ended up 25th and last of all runners.
Friday's action will conclude with the 45-minute Practice 3 at 3:50pm local time.