Approved Chassis:

Must use current, commercially available 41/2” flexi-car production chassis. No prototypes allowed. The approved chassis are listed below:
- Champion 4½” Turbo Flex
- Parma 4½” Flexi II or III
- JK 4½” Cheetah 7, Scorpion I, II & III, one piece
- Trinity/Slot Works 4½” Spyder 2000

Allowed Chassis Modifications:

May solder or glue motor to chassis
May add lead or brass weight
May solder or glue rear oilites
May reinforce rear uprights with piano wire or Slick 7 “U” brace
May file holes in motor bracket, but must retain all of the bracket
May file highest rear axle bushing hole to level rear axle.
May use a piano wire motor brace no longer than 1” and may connect to chassis motor bracket
Fixed or floating pin tubes and guide tongue support are allowed.
Must use oilites/bronze bushings.
Commercially available aluminum pans designed for the chassis being used are allowed.
May reverse pan on the cheetah 7 chassis, However, pan cannot be cut or trimmed and front wheels must be free to rotate.
May interchange pans from the same manufacturer
Soldering of earring back is only modification allowed rear of front axle. No additional bite bars, etc

Disallowed Chassis Modifications:

No ball bearings allowed at rear axle
No axle tube bracing front or rear
No cutting or modifying of chassis in any way. Chassis may be ever so slightly filed to increase or decrease movement of the chassis pan. However, beware that lightening a chassis is prohibited. This rule will be strictly interpreted .