2015 Sport Mod Rules
Same as UMP/AMRA/TSMA Modified rules.
Chassis, Frames and Bodies
UMP/AMRA/TSMA Modified frame and body rules with the following exceptions:
-No coil over shocks
-No tubular front clips allowed.
-Air shocks not allowed.
-All coil springs must be at least four and one half inches outside diameter. Steel
-Canister and/or adjustable shocks are not allowed.
1. Bumpers should be on both front and rear. Front bumper should be mounted frame
end to frame end with the bottom loop parallel to the ground and 6.5″ apart from the
top loop. Should be made of minimum of 1 ¼” tubing and must be able to support car
if lifted by wrecker.
2. Rear bumper and body must not extend beyond width of rear tires.
3. Nerf bars must not extend beyond width of rear tires and must not contain any sharp
edges. Open tubes must be capped.
4. Rear bumper may be constructed of tubing or flat stock, and must protect fuel cell.
Center of bumper, front and rear, must be 18″ from ground. (2″ tolerance). No wider
than 5″ past the rear frame rails. Open tubes must be capped.
1. Must consist of continuous hoops not less than 1.50 inch diameter and must have a
wall thickness of at least .095.
2. Must be frame-mounted in at least 6 places. Roll bar padding required in driver
3. Must consist of a configuration of front to rear hoops connected by tubing on the
sides or side hoops. Driver’s head should not protrude above the cage with helmet
on and strapped in driver’s seat. Roll cage must be securely supported and braced.
4. Low carbon, mild steel tubing is recommended. No brazing or soldering allowed.
5. Protection of feet is mandatory. Bar across back of engines with vertical bars and
rub rails, or similar protection.
6. No brace bars forward of cage may be higher than stock put height.
7. A minimum of 3 driver side door bars must be parallel with the ground as possible
and located perpendicular to the driver so as to provide maximum protection for
driver, but without causing undue difficulty in getting in or out of the vehicle. The
sidebars must be welded to the front and rear of the roll cage members. No brazing or
soldering allowed. Door bars less than .095 thickness should have 4 bars at least 1-½
inches in diameter. Driver doorplates required (5″ in front of seat to rear of seat).
Brakes must be operated on all 4 wheels and must lock up all 4 wheels during
inspection. Brake pedal balance bar only adjusting device allowed on car. No Rear
Axle Brake Floater Allowed, Caliper brackets must be solid mounted to the rear-end
housing. No pressure limiting or check valves allowed. All frt. brake rotors subject to
OEM minimum thickness. Rear rotors .810 minimum thickness Front must be vented.
No shutoff valves.
Gasoline ONLY, no alcohol. Racing fuel is allowed.
One 12 volt battery must be securely mounted and shielded inside frame rails.
(Marine type battery box recommended). The (+) cable must be covered. All positive
posts must be covered.
1. OEM Manual Transmission. Must use stock cases, bearing plates and tail shaft
housings for make and model trans being used. At least 1 forward gear and 1 reverse
gear must work. No mini clutches. Cast iron flywheel, no aluminum. 10 and ½
2. OEM Automatic Transmission. All forward and reverse gears must be operational
at time of inspection. Must have working torque converter. 10 inch minimum
3. Bert or Brinn Transmission. Triple disk clutch allowed. Must weigh 2,600 pounds.
Drive shaft hoop is required and must be constructed of at least ¼” by 2″ steel and
should be mounted at least 6″ back from front of drive shaft. Drive shaft must be
painted white. 2″minimum diameter steel shaft.
2,500 for cars with legal 9 inch rear end and OEM Manual or Automatic transmission.
2,600 for cars with Bert/Brinn transmission and/or quick change rear end and/or triple disk clutch.
1. Any passenger car type or truck rear end may be used. Floater recommended 2″
inspection plug recommended to view Spool and/or gear. Carrier may need to be
removed if we cannot see what needs to be inspected.
2. Quick changes allowed but must weigh 2,500 pounds.
3. No limited slip devices allowed. May run full spool, mini spool, or welded rear only.
All Components Must be Steel. No lightened or light weight components allowed.
4. 72″ between back of block and centerline of rear end.
5. Minimum Panhard bar length 19″ center to center of bolt holes. (2010 23inch rear
mounted panhard bar)
6. One pull bar or lift arm only. (2010 solid pullbar centered over driveshaft)
7. No coilovers no where
8. Non gun-drilled axles.
9. All steel rear end. Except for drive caps on floaters and aluminum spacers for leaf
springs. No lightweight spools or ring and pinions.
Tires and Wheels
1. 8 inch wheels.
2. No aluminum wheels, hubs, calipers or A-frames or any other suspension parts
allowed. Plastic wheels are not allowed. Calipers cannot be lightened and must be
OEM. Rotors cannot be lightened or drilled.
3. Any 8 inch racing tire.
A. Engine Block-OEM Cast Iron only. Maximum cubic inch limit of 390. NO 400 blocks!
B. Crankshaft-Must have a stock appearing rear crank flange. Balancing OK, No
lightening, knife edging or reducing of the crankshaft circumference.. Must be cast
iron crank, no steel.
C. Harmonic Balancer-Must be of OEM design with rubber mounted dampener ring
(SFI rating recommended)
D. Connecting Rods-Must be of OEM design (IE If stock rod was “I-beam than
Aftermarket must be “I-beam). Rod length is up to engine builder (does not have to be
OEM length). Rods may use bolt and nut or cap screws to secure the caps.
E. Pistons- Cast or Forged, Flat top or Dished. No domed or gas ported pistons
F. Camshaft-Hydraulic camshaft only. No roller camshafts allowed. Must pull 15
inches of vacuum at 1000 RPM’s. Must have access to vacuum port in manifold. No
G. Cylinder Heads and Valve Train-Must be unaltered approved OEM. All heads
must have been used in a production vehicle. No limited production or special
purpose over the counter only heads allowed. No porting, polishing or unapproved
valve bowl work or other alterations of any kind to heads or intake. 202’s allowed. No
screw in studs. No pin studs. Must use stock diameter valve springs. Stock steel
stamped rocker arms. No beehive springs. No studgirdal. No VORTEC heads.
Polylocks ok. No canted value (Cleveland style) heads! Valve springs can’t be more than 100 pounds with valve closed. No variance, this is a black and white rule.
H. Exhaust-May use aftermarket headers. Exhaust system must be mounted in such
a way as to direct spent gases away from cockpit of vehicle and away from areas of
possible fuel spillage. Exhaust header outlets no higher than midline of the body
sides. Officials may require turn downs on the collectors. Dual exhaust only no “Y”
pipes or 180 headers. No oxygen sensors allowed.
I. Intake-Any cast iron or aluminum intake. No porting or enlarging inside of intake or
gasket matching. No Bowtie, VORTEC, SVO or W2, marine or other special
production intake manifolds. No intake manifold to cylinder head spacers allowed.
J. Carburetor-2 barrell Holley 4412 only. No grinding or polishing of any kind allowed.
All carburetor components manufactured by Holley. No Aftermarket base plates,
metering blocks or carb bodies allowed. No milling or grinding of throttle shaft
allowed, shaft must stay round. The choke and air horn may be removed, this is the
only re-working allowed, must have stock measurements. Carb gauges will be used. 2.
Steel, aluminum or Phenolic adapter plate or spacer allowed. Distance between the
bottom of carburetor and top of intake manifold cannot exceed 1 ¼ inch! Total spacer
height includes gaskets.
K. Fuel Pump-OEM style diaphragm pumps only.
L. Ignition-OEM Stock appearing Distributors only (all components, even coil cover).
Must run stock firing order. No MSD boxes.
M. Cooling System-Cooling system may be modified. Radiator and oil cooler must
not protrude above interior. No electric waterpumps or cooling fans. No sprinkler
systems. Any overflow tubes are to be directed to the ground, between frame rails.
N. Starter-All vehicles must have the capability of starting without being pushed or
pulled. Starter must bolt to engine in factory location.
This is intended to be an economical class. Rules will be strictly
enforced, absolutely no exceptions!
Please note that racing is an ever changing sport so H&L Motorsports, LLC reserves
the right to modify rules as time goes on.
Please contact SOS tech official John Hunt at 740-646-8314 for any additional