KMR Sport's Tom Mills enjoyed a near perfect qualifying session at Oulton Park, claiming a double pole position at the Cheshire circuit.
Mills' time of 1m34.592s put him almost a quarter of a second clear of teammate Jeremy Fairbairn, with Cooper Webster taking third for series newcomers Evans GP.
Colin Queen was next up for Fortec Motorsport, while another new team in the form of Fox Motorsport were fifth with Ginetta Junior graduate Liam McNeilly.
Elite Motorsport duo Josh Irfan and Harri Reynolds were sixth and seventh, with the former the final driver within a second of the pole time.
Harry Burgoyne was just a fraction behind in eighth for Graham Brunton Racing, as he gears up for his first car race, while Ruhaan Alva (Fortec) and Jason Conzo (Oldfield Motorsport) completed the top-10, which was covered by 1.7 seconds.
With the race two grid determined by each driver's second quickest times, Mills' next best lap was just 0.015s slower, and ensured he will start race two from pole as well, almost a second clear of Webster with McNeilly rising to third.
Queen was just a fraction further back, with Irfan and Fairbairn all within a tenth of a second.
The first GB4 race of the season is due to commence at 17.15.
GB4 Championship, partnered by the BRDC, Oulton Park qualifying result (race one grid):
1. Tom Mills, KMR Sport, 1m34.592s
2. Jeremy Fairbairn, KMR Sport, +0.247
3. Cooper Webster, Evans GP, +0.414
4. Colin Queen, Fortec Motorsport, +0.746
5. Liam McNeilly, Fox Motorsport, +0.806
6. Josh Irfan, Elite Motorsport, +0.840
7. Harri Reynolds, Elite Motorsport, +1.287
8. Harry Burgoyne, Graham Brunton Racing, +1.302
9. Ruhaan Alva, Fortec Motorsport, +1.451
10. Jason Conzo, Oldfield Motorsport, +1.718
11. Sid Smith, Fox Motorsport, +1.901
12. Jack Clifford, KMR Sport, +2.216
13. Aditya Kulkarni, Fortec Motorsport, +2.216
14. Dylan Hotchin, Dylan Hotchin Racing, +5.164
15. Thomas Lee, Evans GP, +7.266
GB4 Championship, partnered by the BRDC, second fastest times (race two grid):
1. Tom Mills, KMR Sport, 1m34.607s
2. Cooper Webster, Evans GP, +0.961
3. Liam McNeilly, Fox Motorsport, +1.051
4. Colin Queen, Fortec Motorsport, +1.082
5. Josh Irfan, Elite Motorsport, +1.110
6. Jeremy Fairbairn, KMR Sport, +1.160
7. Harry Burgoyne, Graham Brunton Racing, +1.318
8. Harri Reynolds, Elite Motorsport, +1.380
9. Ruhaan Alva, Fortec Motorsport, +1.692
10. Sid Smith, Fox Motorsport, +1.887
11. Jason Conzo, Oldfield Motorsport, +1.914
12. Aditya Kulkarni, Fortec Motorsport, +2.437
13. Jack Clifford, KMR Sport, +2.439
14. Dylan Hotchin, Dylan Hotchin Racing, +5.166
15. Thomas Lee, Evans GP, +8.774