For the 2016 season 191 will have a new Sport Mod class which was designed for the entry level budget minded racer. The tentative rules have been released and are listed below:
- UMP/AMRA/TSMA Modified chassis, body and frame rules with the following exceptions:
- No coil over shocks
- No spoilers
- No tubular front clips
- No air shocks
- All coil springs must be at least four and one half inches outside diameter. Steel springs only
- No canister type or adjustable shocks
- Steel shocks only
- Transmission
- 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. Flywheel – SFI approved/recommended
- OEM Automatic Transmission. All forward and reverse gears must be operational at time of inspection
- Bert or Brinn Transmission allowed with a 50 lb weight penalty
- Rear Ends
- Any passenger car type or truck rear end may be used
- 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 center line of rear end
- Minimum Pan-hard bar length 19″ center to center of bolt holes. (2010 23inch rear mounted pan-hard bar)
- One pull bar or lift arm only. (2010 solid pullbar centered over driveshaft)
- No coil-overs any where
- No gun-drilled axles
- Quick Change rear ends allowed with a 50 lb weight penalty
- Tires and Wheels
- 8 inch steel wheels only
- 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
- Any 8″ racing tire
- Drive Shaft
- 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
- Engine
- Maximum cubic inch limit of 390
- OEM cast iron block only. No aftermarket blocks allowed
- OEM cast iron cylinder heads only. No aftermarket heads allowed
- No canted value (Cleveland style) heads allowed
- No screw in studs allowed
- No guide plates allowed
- Stock steel stamped rocker arms only. No aftermarket rocker arms allowed
- Stock diameter valve springs only
- Hydraulic camshaft only
- Must pull 15 inches of vacuum at 1000 RPM’s. Must have access to vacuum port in manifold
- Aftermarket headers OK
- Any cast iron or aluminum intake allowed
- Unaltered Holley 2 barrel 4412 carb only. Venturi and base plate must retain stock size
- 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.
- OEM style fuel pump only
- Stock type distributors only. No aftermarket ignition boxes MSD, Crane, etc.
- Fuel
- Gasoline Only, no alcohol or E85
- Weight
- Base Weight is 2450 lbs
- Add 50 for Bert/Brinn
- Add 50 for Quickchange
- Base Weight is 2450 lbs