Max Cook picked up where he left off a fortnight ago as he topped the timesheets in opening free practice, 0.298s ahead of Dan Brooks.
Sam Laffins ended the session in a close third, ahead of Jack Bednarek as Aaron Silvester rounded out the top five.
Pirelli National Junior Superstock with MotoNovo Finance, Cadwell Park, Free Practice One:
1. Max Cook (Ugly & Co by Binch Pro) 1.32.334s
2. Dan Brooks (R4R Vision Team) +0.298s
3. Sam Laffins (Cheshire Mouldings Kawasaki by JR Performance) +0.592
4. Jack Bednarek (CF Motorsport) +0.714s
5. Aaron Silvester (A&J Racing) +1.042s