Davey Todd took early charge of the action at Oulton Park as he topped the timesheets at the end of the first free practice session of the season.
Aboard the Cheshire Mouldings BMW by TAS Racing, he beat Joe Talbot by 0.523secs with a best lap of 1min 36.310s.
Third quickest was David Allingham, who led Ash Beech, as Tom Ward ended the session fifth.
Pirelli National Superstock with Moneybarn Finance, FP1:
1. Davey Todd (Cheshire Mouldings BMW by TAS Racing) 1min 36.310s
2. Joe Talbot (JR Performance Racing) +0.523s
3. David Allingham (SMS/Nicolls Oil Racing) +1.283s
4. Ash Beech (Jones Dorling Racing) +1.822s
5. Tom Ward (Armada Marine Cables Racing) +2.391s