Whanganui driver Dylan Smith (53V) finished just a whisker behind Betts in the New Zealand championship, and recently finished second to Dewar in the North Island Minisprints at Te Marua Speedway in Wellington.
Dewar also leads the Oval Superstars Tour series points, ahead of Smith and Elliot Heron (72P).
The West Coast Minisprints will be contested over three heats, before the 30-lap Oval Superstars Tour finale to end the night.
To create a point of difference, the top points scorers in the West Coast event will start of the back of the field for the finale, and will have to pass a bunch of cars to make their way to the front.
That should ensure an action-packed race.
The make-up of the West Coast Stockcars field was uncertain at the time this went to press, but local drivers will be determined to keep the trophy in Whanganui.
Defending champion Callum Sturzaker has been in fine form this season, with his highlight being third place in January's New Zealand Stockcar Grand Prix at Woodford Glen in Christchurch.
Trazarn Ryland-Annabell (33V) finished third last season, but has a new car this year, and has shown plenty of speed and aggression.
Trazarn Ryland-Annabell, 33v, puts Kyle Lampp 772P up the wall at Oceanview.
Dion Mooney (6V) finished second ahead of Sturzaker in the Grand Prix, and is a proven, consistent performer as well as a former West Coast titleholder.
Kaelin Mooney (26V) has had a fantastic debut season in the Stockcar class.
He won the Charlie Berntsen Trophy event at Whanganui, and made the top tier at all three Speedway NZ championships in the Stockcar class this season.
Veterans Blair Lockett (89V) and Francis Potaka (52V) are seasoned competitors, while the likes of Mark Johnston (78V), Blair Reeves-Smith (212V) and Hailey James (18V) are all capable of winning.
Superstocks, Youth and Adult Ministocks and Production Saloons will also race, for the penultimate time this season.
The pit gates open at 3pm, public gates at 4.30pm and racing starts at 6pm, with 20 races on the programme.
