Note: This is my interpretation of the body rules for SIMS, ARA, & IMCA.

If you build a car by SIMS body rules it would appear to be legal in all sanctions.

Check with your (Sanctioning Body) rules for clarification.

 

  Recommended IMCA Southern Sport Mod. ARA Limited Mod. Sims Limited Mod.
A. Front Bumper Height 23" Max 23" Max 23" Max
B. Roof Height 58" Max. 58" Max 58" Max 58" Max
C. Center front spindle to front bumper 39" 40" Max. 39" Max. 40" Max.
D. Hood sealed off from drivers compartment 5" Max. sides Hood Sides 5" Max.  Hood Sides 8" Max.  Hood Sides 5" Max. 
E. Hood Scoop Hood Scoop Allowed Hood Scoop Allowed Hood Scoop Allowed
F. Ride Height to bottom of Frame Rails 5" Max. 5"  Max.    5"  Max. 
G. Wheel Base109" Max. to 107" Min. 109" Max. to 107" Min. 109" Max. to 107" Min. 109" Max. to 107" Min.
H. Door Height 31" 31" Min. 22" min. to 31" Max. 31" Max.
I. Center rear axel to front of body 67" Min. to 76" Max. 67" Min. 76" Max. to 67" Min. 67" Min.
J. Window Opening  9" Min. to 15" Max. 16" Max. to 9" Min.  9" Min. 15" Max. to 9" Min.
K. Roof Size                      53" Max. to 32" Min. Length                  53" Max. to 32" Min. width 53" Max. to 32" Min. Length 53" Max. to 32" Min. width 53" Max. to 30" Min. Length 55" Max. to 30" Min. width 53" Max. to 32" Min. Length         53" Max. to 32" Min. width
L. Total Body Length 121" Max. to 98" Min. 121" Max. to 98" Min. 121" Max. to 98" Min.
M. Center rear axel to rear of body 48" Max. to 31" Min. 48" Max. to 31" Min. 49" Max. to 31" Min. 48" Max. to 31" Min.
N. Quarter Panel Height 35" 36" Max. 35" Max. 35" Max.
O. Rear Bumper Height 26" Max. 26" Max. 28" Max. 28" Max.
P. Interior Slope 6" Max. 3" over length of door and 3" over length of rear deck. Interior Slope 6" Max. Interior Slope 7" Max. 6" Max. 3" over length of door and 3" over length of rear deck.
Q. Alum. or Lexan Spoiler  See spoiler page    
R. Rear of body deck height 41" Max. 41" Max. 42" Max. 41" Max.
S. Body Width 67" Max. to 55" Min. 67" Max. to 55" Min. 68" Max. to 55" Min. 67" Max. to 55" Min.
T. Rear Panel Rear Panel 9" Optional Rear Panel 9" Optional Rear Panel 9" Optional
U. Outside width of tires 77" Max. 77" Max. 77" Max.
         

Spoiler Rule: ( Spoiler Width cannot exceed width of Body )

ARA Rear spoiler is allowed with a maximum of material of 15" measured along the spoiler from the deck to the top, NOT straight up and down. A maximum of four(4) braces are allowed, one on each side measuring a maximum of the angled height of the spoiler X 24" long. Only one spoiler is allowed except for gremlin roofs. Gremlin roof spoiler can be no more than 4" and supports on each side cannot go further forward than 6". Aluminum or lexan OK. Spoilers may not go beyond back bumper. If spoiler is more than 7", you must use lexan above that for vision purposes.

SIMS Rear spoiler is allowed, with a maximum use of material of 15", measured along the spoiler, from the deck to the top, not straight up and down.  A maximum of four braces are allowed, one on each side, measuring a maximum of the angled height of the spoiler x 24" long.  Only one spoiler is allowed.  Aluminum or Lexan okay.  Spoiler may not go beyond back bumper.

IMCA Southern Sport Mod. Same

SIMS Roof rear sail panels are allowed one 90 degree bend along the top edge of the sail panel, but must be less than 1” wide. Gremlin style roofs not allowed.
No more than 6" of total rake allowed on the body deck.  A maximum of 3" of rake (of the 6" total) is allowed in the door section and a maximum of 3" of rake is allowed in the quarter panel section. If you keep the door section level, then you are only allowed 3" of rake in the quarter panel section.
Minimum ride height is 5" from ground to side frame rails.
Plastic body panels and plastic filler panels are not allowed.
No convertibles, unless special race.
Cars must have full deck interior from one side of the body to the other. Decks must be aluminum or sheet metal.

FENDERS:
Quarter panels must be 90 degrees to the ground, with a maximum of a 45 degree bend 4" from the bottom of the doors and quarters and 2" on top.

FIREWALL:
Must be metal or aluminum with minimum sized holes for throttle, etc. Firewall must be sealed from engine compartment.

FLOOR:
Must be metal or aluminum. Must cover entire driver’s cockpit to front edge of seat.

BUMPERS:
A. Two (2) bar front bumper is mandatory.  Maximum size is = 1-1/2" X .095".
B. One single bar rear bumper is required.  Maximum size is = 1-3/4". The required fuel cell protection bar (maximum size = 1-1/2" X .095") may be attached to the rear bumper.

HOOD:
A. Must cover completely the  top of engine and radiator.
B. Must extend from the nose piece to the deck.
C. Hood may be made of metal, aluminum, or fiberglass.
D. Hood must provide a seal to the top of  the engine compartment.
E. Cannot cover side of engine more than 5".
F. Hood scoops okay.