See 2019 KPX Supplementary Rules:
Briggs 206 Classes: Pump gas. Spec octane and gas station decided before race weekend. The specified gas shall be the only gas allowed during the race day and is subject to tech.
IAME Classes: Fuel VP C12. Oil Motul 2T Grand Prix mixed 8oz per/gal. The specified fuel shall be the only fuel allowed during the race day and is subject to tech.
2019 Class Structure: