LIMITED MODIFIED RULES
The rules and/or regulations set forth herein are designed to provide
for the orderly conduct of racing events and to establish minimum
acceptable requirements for such events. These rules shall govern
the condition of all events, and by participating in these events,
all participants are deemed to have complied with these rules. NO
EXPRESSED OR IMPLIED WARRANTY OF SAFETY SHALL RESULT FROM PUBLICATIONS
OF OR COMPLIANCE WITH THESE RULES AND OR REGULATIONS. They are intended
as a guide for the conduct of the sport and are in no way a guarantee
against injury or death to a participant, spectator, or official.
The race director shall be empowered to permit reasonable and appropriate
deviation from any of the specifications herein or impose any further
restrictions that in his/her opinion does not alter the minimum
acceptable requirements. NO EXPRESSED OR IMPLIED WARRANTY OF SAFETY
SHALL RESULT FROM SUCH ALTERATION OF SPECIFICATIONS. Any interpretation
or deviation of these rules is left to the discretion of the officials.
Their decision is final.
the Limited Mod rules set forth below it is explained what you can
do, ANYTHING else will result in being DQ'ED. NFS reserves the right
to add weight to any car, any where at any time to keep all cars
TRANSMISSION, Small Block GM 350 Only. Anyone wanting to build a
Ford engine must consult with tech director before you start your
1. Block, Factory Production 350 GM No aftermarket blocks of any
kind, 2 or 4 bolt, 1 or 2 piece rear main seal, Maximum overbore
0.60 + 0.10 for wear, No grinding on inside or outside of block,
No 400 blocks, No stroking or destroking, May zero deck block, At
no point can piston protrude above deck, May install screen filters
in lifter valley.
2. Rods, Must be 5.7 inch rod, I-Beam rod only. May have thru bolts
or caps screw type ARP OK, May be floated, No other rods or sizes,
No Polished, No aluminum, May use Eagle or Scat if they meet above
rules. Must be stock appearing.
3. Pistons, May use 2 or 4 eye brow, cast or forged, Must have stock
pin height for 5.7 rod and 3.48 stroke crankshaft, May use short
skirt, No skirt piston is NOT allowed!!!
4. Minimum weight for piston, wristpin, rod, and rings, is 1194
grams, dry weight, NO TOLERANCE!!!
5. Crankshaft, Cast or steel, Stroke must be 3.48 inch, 48 pound
minimum weight NO TOLERANCE, No knife edge cranks, may add heavy
weight to balance, No grinding on crankshaft, No polishing of crankshaft
counterweights, Must be stock appearing, Must have casting number
on crankshaft, May use eagle or Scat if they meet above stated rules.
6. Harmonic Balancer, Must be a minimum of 6.75 inches in diameter,
and must be cast or steel with elastomer insert, No fluid dampers
or solid dampers.
7. Balancing, May balance rotating assembly, No grinding, may add
heavy weight to balance.
8. Camshaft, 390/410 maximum lift, Must be hydraulic flat tappet,
No roller, No solid.
9. Lifters, Must be hydraulic, No solid No roller, No anti pump
up, No Rhoads type lifters, Must be stock diameter for 350 GM production,
Must be adjusted to zero lash.
10. Pushrods, 7.800 length and stock diameter.
11. Rocker arms, Must be stamped steel, 1.5 ONLY, No roller or roller
tip, May use poly locks, No stud girdles.
12. Timing chain and gears, May use double roller, May use thrust
bearing on top gear, May use cam button, May use multiple keyed
crank gear. May degree camshaft. No gear drive, No belt drive, No
adjustable cam gear.
13. Heads, Any factory production open chambered head that meets
the rules stated below,
Maximum valve size 194/150, Valve stem at base of valve can have
a maximum of 0.30 neck down, No undercut valves, No swirl polished
valves, May use stainless valves, Minimum72 cc combustion chamber
on heads, 3 angle valve cuts OK, Must have 11/32 valve stem diameter,
Must be stock length valve, Heads must have OEM runner sizes for
casting being used, No porting, gasket matching or acid dipping,
No grinding on inside or outside of heads, Must have legible casting
number, No angle milling, May use screw in studs 3/8 inch diameter
only, May pin studs, All studs must be 3/8 inch diameter, May use
guide plates, NO double hump heads, No Vortec heads, No Bowtie heads,
No angle plug heads, No SR heads, No aftermarket heads of any kind.
14. Intake, Any cast or aluminum intake, Must have casting number,
May use cooling lines, No porting or polishing, No acid dipping,
No handmade intakes, No gasket matching.
15. May use lifter baffle.
16. May use Evac system.
17. Distributor, Factory OEM stock type, May lock advance, May change
module, May use printed circuit board module, May use hot coil,
No small MSD distributors, No MSD boxes, No adjustable rev limiters
other than what comes on the printed circuit board module which
is mounted inside of distributor.
18. Carburetor, Holley 4412 500 CFM, single fuel line, Must have
stock metering block, May change accelerator pump to 50 cc, May
remove choke shaft and plate, May change jets, May change or block
off power valve, Must have complete air horn, Must use standard
type air filter housing, No air flow devices inside air filter housing,
Must have solid top on air filter.
Holley 1850, 600 CFM, single fuel line, Must have stock front metering
block, May change accelerator pump to 50 cc, May remove choke shaft
and plate, May change jets, May change or block off power valve,
Must have complete air horn, May use rear jet plate, May use quick
change secondary vacuum pod, May use center hung float bowls, Must
use a Mr. Gasket dual line fuel line maximum diameter 3/8 inch or
equivalent. No Fuel log, No return line, No bypass, No secondary
metering block, NO BILLET PARTS ON ANY CARBS.
19. Carb Adapter, If carb will bolt directly to intake you cannot
run an adapter or spacer and your gasket thickness is a maximum
of 5/16, If an adapter is required the maximum thickness of adapter
and gaskets is 1 1/2 inch, Adapter must be steel or aluminum, No
20. Fuel pump, May be racing pump, Must be mounted in stock position
on block, Maximum pressure 7 PSI, No belt driven, No tandem fuel/power
21. Water pump, May use aftermarket aluminum racing pump, May use
22. Radiator, May use aluminum racing type.
23. Exhaust, Headers allowed, May be stepped, No Tri Y headers,
24. Power steering pump, Must be mounted on left front of engine
(drivers side), No tandem fuel/power steering combos.
25. Flywheel, Clutch, and Pressure Plate, Flywheel minimum weight
14lbs, clutch disc minimum diameter 10.5 inches, may have spring
center or solid, pressure plate must be stock replacement type,
No lite weight assembly. All parts must be steel, No aluminum components.
26. Transmission, Cast iron only, Must be 3 or 4 speed, Must have
all working gears, Must have reverse, No lightning of any components,
Must be OEM stock.
27. FUEL, Passenger car pump gas only, No racing fuel or any additives
of any kind, Must contain 10% Ethanol, Must pass NFS fuel test.
28. FUEL penalties, 1st offense 10 points and $50.00 fine, 2nd offense
lose all points and monies from that nights event and $125.00 fine,
3rd offense lose all points for the season and $250.00 fine.
29. Any driver getting out of his car during an event will be DIQUALIFIED
from that event, UNLESS, the vehicles is upside down or showing
signs of Fire.
30. ANY CAR OR DRIVER FOUND TO BE ILLEGAL WILL BE DISQUALIFIED FROM
THAT NIGHTS RACING EVENT.
MINIMUM WHEEL BASE 108 INCHES MAXIMUM WHEEL BASE 108 INCHES 1 INCH
1. Upper control arm MUST be steel, adjustable and aluminum cross
2. Lower control arms May be Stock type or Tubular. MUST be steel.
3. Tie rods May be OEM type or Swedge tube and heim joints inner
4. All steering components must be steel.
5. SHOCKS, One shock per wheel, Steel body only, Split valve OK,
No threaded body shocks, No adjustable shocks, No Schrader valve
shocks, No rebuild able shocks, No aluminum shocks, No shocks with
any type of Allen plugs or any openings at all into the body of
shock. No coil over shocks on front.
NO BUMPS STOPS
6. No aluminum parts any where in the suspension.
7. May run Coil overs on rear, same as shock rule above, may use
a 2.5 spring or a 5 inch spring but must be same on both sides.
8. Springs must be steel No composite.
9. Rear end, 9 inch or Quick Change, No Ratchet rear diffs, No limited
slip diffs, Must be fully locked, No aluminum tubes,
10. Birdcages Must be steel.
11. Swedge tubes Must be steel.
12. May run any type top link.
13 May use shock on top link of rear end.
14. Any type J bar.
1. No floated Brakes.
2. Must have 4 wheel brakes.
3. May use RF shut off.
4. Calipers must be steel stock OEM No aluminum.
5. May use brake bias adjuster.
6. Rotors Steel only
7. May use aftermarket peddle assembly.
1. Deck Maximum width 68 inches.
2. Deck can have a maximum of 3 inches of taper from rear to front.
3. Top of deck must stop at motor plate at front.
4. Minimum deck height 28 inches, Maximum deck height 38 inches.
5. Spoiler width Maximum 68 inches.
6. Spoiler height maximum 6 inches, bends will not count as long
as they are at 90 degree or at level bends if they have any angle
upward they will be counted in spoiler height.
7. If spoiler is not incorporated into sail panels the end piece
maximum height will be 6 inches X 10 inches long.
8. Center spoiler brace 6 inches high X 10 inches long One (1) only.
9. Roof, Maximum width 50 inches, Maximum length 56 inches.
10. Roof rake from rear to front maximum 3 inches.
11. Door panels may extend 6 inches forward of front deck.
12. Door and quarter panels minimum 4 inches from ground.
13. No closing of engine compartment, No air dams under deck or
14. Front nose must be no wider than outside of the front of the
frame horns, and must not extend past the leading edge of front
bumper, top of bumper must protrude above nose piece, Maximum nose
and bumper length 42 inches from the center of spindle, minimum
6 inches of ground clearance for front nose.
15. Window sails must start even at top of roof and taper in a straight
line to rear spoiler, must not protrude any higher than spoiler,
solid window sails OK or if you wish you may cut out windows in
them you must cut but sides not just one.
Tires and Wheels,
1. Wheels, 8 inch steel only.
2. Bead locks OK on all or any corner.
3. Hoosier 26.5 or 27.5 A, D, H, or Medium.
4. No grooving, or siping.
5. No tire Doping.