Popular state-level category Improved Production is a surprise inclusion on the Clipsal 500 Adelaide support bill for 2017.

A 32-strong grid of the modified production-based touring cars are expected to front for the March 2-5 event, which was launched in Adelaide today.

The category, which boasts championships in every Australian state as well as an annual single-event national title, features a wide variety of machinery.

Improved Production replaces V8 Utes which has been a stalwart of the event since the category was launched in Adelaide 15 years ago.

The current Ford and Holden Utes will be phased out next season ahead of the debut of the new dual-cab based SuperUtes class mid-year.

Clipsal 500 organisers also confirmed the return of the Dunlop Series, Australian GT, Carrera Cup, Touring Car Masters, Stadium Super Trucks and Aussie Racing Cars to the program.

The announcement of the support category line-up follows recent news that the event will return to its tradition twin 250km race format for the Supercars.

Saturday’s 250km of racing had been split into two 125km heats for the last three years.

VIDEO: Clipsal 500 launch