Scott Swann made the best of the wet conditions during qualifying to storm to pole, beating Tim Neave by 2.033secs with a best lap of 2min 11.792secs.
In a session hit by rain, Edmund Best was third while points leader Davey Todd will head the second row, with Jamie Lyons fifth.
Pirelli National Superstock with Moneybarn Vehicle Finance, qualifying:
1. Scott Swann (Swann Racing) 2min 09.759s
2. Tim Neave (MasterMac Honda) +2.033s
3. Edmund Best (Symcirrus Motorsport) +2.374s
4. Davey Todd (Cheshire Mouldings BMW by TAS Racing) +2.583s
5. Jamie Lyons (JLR by Ability Energy Scotland Ltd) +2.789s