National Superstock 1000cc champion Richard Cooper and British Superbike star Christian Iddon head the entry for this weekend's Sunflower Trophy event.
Cooper defends the title he won on his Buildbase Suzuki last year and is joined in the team by Eglinton's David Allingham and newcomer Leon Jeacock.
Bishopscourt lap record holder Iddon, 34, returns to the meeting for the first time since 2016 on his Tyco BMW.
Five races are scheduled for Friday, with the remaining 13 on Saturday.
Stockport-born Iddon picked up the British Superbike Riders' Cup title at Brands Hatch last weekend, awarded to the rider who finishes seventh in the overall standings, behind those involved in the end-of-season Showdown.
Other leading riders confirmed for the Superbike races include former Irish Superbike champion Charles Stuart on a J McC Roofing Kawasaki, Carl Phillips, Alistair Kirk, Nico Mawhinney and Gerard Kinghan.
The McAMS Yamaha BSB team field British Supersport regular Harry Truelove in their colours.
Manufacturer switch for Allingham
Allingham rode the Buildbase Suzuki at the final round of the BSB series at Brands Hatch and says he straight away felt more comfortable with the machine than the Yamaha R1M he had ridden all season for his father's EHA Racing team.
"To be honest, I never really gelled with the Yamaha R1M, And with crashes due to trying to override problems, I was not enjoying my racing," said Allingham.
"Stuart [Hicken] offered me a run on the Suzuki last week at Brands, and straight away, I felt so much more comfortable.
"So I've got another chance to ride the bike this weekend at Bishopscourt, which I'm looking forward to as I don't get the chance to race in front of my home fans often.
"I'm going to out to enjoy myself, I want to get the feel-good factor back again."
Seeley among Supersports
Among those contesting the Supersport races will be former British 600c champion Alastair Seeley, who is still trying to fully recover from the effects of a wrist injury recently sustained at Oulton Park.
Also part of the entry is newly-crowned British Superstock 600c champion Korie McGreevy, who clinched that title last weekend.
Richard Kerr, Simon Reid, Ross Patterson and Sam Laffins, all regular competitors in British short-circuit series, will also be on the grid at the County Down track.
Aghadowey's Eunan McGlinchey, rides for McAdoo Kawasaki Racing in the 600cc class and the Supertwins outings, where he will come up against KMR Kawasaki-mounted Jeremy McWilliams, Ian Lougher on the Mark Coverdale Paton, Dominic Herbertson and Ulster Supertwin champion Gary McCoy.