Sullivan Mounsey beat Lucas Brown to the quickest lap of the first session as he clocked a 1min 627secs at Knockhill.
Johnny Garness was third quickest, just ahead of his team-mate Carter Brown as Ted Wilkinson rounded out the top five.
Honda British Talent Cup, Knockhill, FP1
1. Sullivan Mounsey, (Wilson Racing /J&S Accessories)
2. Lucas Brown (Amphibian Scaffolding) +0.468s
3. Johnny Garness (MLav VisionTrack Academy) +0.646s
4. Carter Brown (MLav VisionTrack Academy) +0.905s
5. Ted Wilkinson (RMB Racing) 0.981s