Evan Belford led the way as the British Talent Cup field hit Knockhill for the first time this year, clocking a 53.689sec lap to beat Amanuel Brinton by 0.895secs.
Third fastest was Rhys Stephenson, who finished just ahead of Sullivan Mounsey in fourth with Harrison Dessoy fifth.
R&G British Talent Cup, free practice one:
1. Evan Belford (City Lifting/RS Racing) 53.689s
2. Amanuel Brinton (Kovara Projects/RS Racing) +0.895s
3. Rhys Stephenson (Rocket Racing) +0.942s
4. Sullivan Mounsey (Wilson Racing/Maddison Media) +0.996s
5. Harrison Dessoy (Microlise Cresswell Racing/Easter Garage Racing) +1.070s