2023 LATE MODEL STOCK CAR RULES
COMPETING MODELS 1. 1970-2023 rear wheel drive model cars with a minimum wheelbase of 103” Wheelbase. Rules for the race cars are all the same. Different weights or Carbs are used to equal different motor combinations. It is a priority for Dillon Motor Speedway to make different engine combinations on a equal playing field. DMS and officials will do their best to make this happen.
1. Aftermarket Stock appearing bodies allowed. 2011-2023 Mustang and Camaro allowed.
2. Aftermarket composite or metal body must meet speedway ABC template specifications.
3. All cars must be painted and lettered professionally.
4. Hood must fit to windshield.
5. Rocker panels may be fabricated. All measurements such as motor, fuel cell height etc will be measured with car on 4 inch blocks all around
6. No “panning” underside of car.
7. Front and rear windshields must be lexan. Clear lexan or plexiglass may be installed in the rear quarter windows. Maximum 10” vent window allowed.
8. Speedway approved window net must be installed in the driver’s side window opening.
9. Body roof height minimum 48 inches with driver measured on 4 inch blocks 10” behind windshield. Rear Spoiler height maximum from the ground – 39” measured on 4 inch blocks
10. Rear spoiler 5” high with maximum 54” width.
11. Wrecker hookup required on front and rear of car.
1. Stock OEM front sub frame allowed. Lower control arm mounts must be centered.
2. Tubing front sub frame allowed. Lower control arm mounts must be centered.
3. Frame rails minimum 2”x 3” x .083 wall thickness. Grandfathered frames or underslung
chassis must have 25 lbs. mounted on chassis above rear end housing.
4. Frames must be perimeter style. Front and Rear sub-frames must be centered to roll
5. Chassis rails must be perimeter style.
6. A steel interior must separate the driver from the engine compartment and fuel tank. A metal dash must be in installed in the driver’s compartment.
7. Floorboard may be raised ten inches to the drive shaft tunnel to the top of the door bar
and seal off to allow clearance for headers. No boxed interiors.
ROLL CAGE 1. A complete speedway approved roll cage. 2. Roll cage must be constructed of roll bar tubing with a minimum outside diameter of one and three-quarter 1 ¾” inches x .083 wall thickness. 3. Roll cage must be centered on the main frame rails. Perimeter style. 4. Main roll cage uprights must be on top of the frame rails. 5. Full cage is required with four uprights and four top bars. 6. Minimum of four bars in driver’s and passenger’s door required. 7. All roll bars within drivers reach must be padded.
FRONT SUSPENSION 1. Screw jacks allowed on front and rear. 2. Wheel spacers may be used. Offset for alignment only. 3. OEM or Fabricated spindles allowed. Must be the same offset left to right. 4. Lower A-frames design may be OEM or Fabricated (minimum size 1 ¼” steel) 5. Front lower control arms must be equal length left and right. 6. Upper A-frames may be fabricated. 7. Front sway bar may be OEM or aftermarket. 8. Coil-over suspension allowed. 9. Aftermarket hubs allowed. 10. No titanium suspension parts allowed.
STEERING 1. No Rack and Pinion steering allowed. 2. All cars must be equipped with OEM type steering. 3. Steering components may be aftermarket.
SUSPENSION 1. Three link, leaf spring or truck arm suspension allowed. 2. A metal fabricated pan-hard bar is allowed. 3. Fabricated upper link allowed. 4. Damper shock permitted on rear suspension. 5. Rubber bushing, metal bushing, teflon bushings or heim joints allowed. 6. Three link arms (min 1 ¼) must be steel tubing, and a maximum of 30”. 7. Truck arms must be magnetic steel. 8. Lowering blocks and trailing arms may be adjustable. 9. Rear sway bar not permitted. 10. Aftermarket hubs allowed. 11. No Titanium rear suspension parts allowed.
REAR END 1. Rear end may be car, truck, floater, quick change or 9 inch. 2. No cambered rear ends. +/- .4 Grace. No aluminum tubes. No aluminum yokes. 3. Detroit Locker or spool only. No torque limiting devices allowed. 4. Only steel third members (9 inch chunks) allowed. 5. No titanium rear end parts allowed
SPRINGS and SHOCKS 1. Alum or Steel Tie rod or spherical end shocks allowed. No External Reservoir Shocks. 2. Coil spring min diameter 2 ½”. Coilover eliminator allowed. Only rubber and metal washers allowed on shock shaft. 3. One shock and One spring per wheel. Helper spring allowed
BRAKES 1. Multi piston metal brake caliper permitted.
2. Steel disc brakes may be used on front and rear. All 4 wheels must work. 3. No titanium brake parts allowed.
WHEELBASE and TREADWIDTH 1. 103” minimum. 2. Cars must not exceed the maximum allowable tread width of 66 inches.
AIR CLEANER 1. Round air cleaner element minimum of 12 inches; maximum of 17 inches in diameter permitted. Front facial may only be half the diameter. 2. Top and bottom of air cleaner must be the same size. 3. Element must be minimum of 1 ½ “and a maximum of 4 inches in height. 4. Dry type paper element only. 5. No tubes, funnels or anything which may control the flow of air are permitted. 6. Base of air cleaner cannot extend higher than carburetor choke horn on 2bbl carb. 7. Base of air cleaner on 4 barrel carb no more than 1 ½”above mounting ring of carb. 8. No cold air boxes or cowl induction allowed.
TRANSMISSION and FLYWHEEL ASSEMBLY 1. Automatic, 3 or 4 speed transmissions permitted. Floor shifts optional. Two speed will be allowed to compete with weight penalty. See weight. 2. All gears must be in working order. 3. Heavy duty OEM steel clutch permitted. 4. A metal Multi-disc clutch allowed. Minimum 5 ½ disc size. 5. Hydraulic clutch control permitted. 6. Blow proof bell housing permitted. Must have speedway approved scatter shield protector or steel bell housing. No reverse mount starters. 7. Bottom of bell housing may be cut for clutch service, inspection and ground clearance. 8. Drive shaft must be of magnetic steel only. Drive shaft should be painted white with safety loops attached to the bottom of car for safety.
EXHAUST 1. Headers will be permitted. Header wrap or coating allowed. 2. No step headers, 180 degree, crossover, or merge pipes allowed. 3. OEM stock cast iron manifolds permitted. 4. All LH exhaust must exit behind the driver.
ENGINE LOCATION 1. Engines may be interchanged from one body manufacturer to another. 2. Chevrolet engine must be centered (3/8” grace) in chassis and center of forward most spark plug hole of the right side head inline with upper ball joint as run in race. 3. Ford & Dodge engine LMS must be centered (3/8″ grace) iin chassis and center of forward most spark plug hole of the right side head inline with upper ball joint as run in race. 4. Minimum crankshaft height is 12”, measured from the center of crank pulley to the ground 5. Grandfather clause in effect.
COOLING SYSTEM 1. Aluminum radiators permitted. Internal oil cooler allowed. 2. Overflow hose recommended. 3. Antifreeze is not permitted. ($200 fine) 4. Electric fans are permitted.
1. Electronic or point type ignition allowed.
2. Only 1 stock appearing coil permitted. Distributor may be locked or welded in all engines
3. Only one 12-volt battery permitted. Stock firing order required.
4. Only one MSD ignition box permitted. No magnetos. No adjustable timing controls.
5. MSD claim rule, $300 by speedway or any driver that completed the late model race.
6. Ignition box must be visible and out of the reach of the driver.
7. Starter must mount in original location.
8. No open ended wiring in driver’s compartment.
9. Tachometer must be able to unhook. No digital readout gauges.
10. Any type traction devices are not allowed. No computerized systems are allowed.
11. All ignition systems must be acceptable to speedway officials.
FUEL and FUEL SYSTEM 1. 100% Race Fuel or 100% Non Ethanoil Pump Gas is the ONLY Fuel allowed. No mixtures. 2. All Fuel must pass Speedway Fuel specifications. 3. Fuel cells are mandatory and mounting of them must be speedway approved for safety. 4. Fuel cells must be securely strapped down with no less than 1/8” steel straps. 5. The maximum capacity allowed is 21 gallons. 6. Fuel cells must have 8” minimum ground clearance. 7. Fuel cell must be mounted in approved steel can. 8. Fuel may be added for weight check.
WHEELS and TIRES 1. 10” Max width. 15” Steel wheel only. Same offset on all 4 wheels. Track Supplied Wheels are 5″ offset 2. Air bleeders will not be permitted. 3. Tires used for qualifying and race must be approved by the speedway. 4.Any car tires from any source other than speedway supplier will be disqualified, a $500 fine imposed. 5. No chemical tire treatment allowed. Durometer and sniffer enforced. Tire Code Scanner may be used.
6. IF DMS Track Supplies Tires on Track Wheels will be Released during practice on race weekends. Any wheel that is damaged when turning in after the race will be a $75 Charge 7. DMS class tire for 2020 Season is Hoosier F-45. Teams will be allowed 2 new tires each week. After the said event those 2 new tires that have been run that night at least 1/2 the event can be left in the tire building to use next week. The next week you will be allowed 2 new tires to go along with your two tires left in tire building. Any tire that has not been run at least 1/2 the race will be traded for a scuff tire from the track. New Tire Sets will be bingo drawn and each set will be equally graded. A newcomer that comes in for his first race will be allowed to pick their two scuffs tires from the “A” stack of tires. If more than one new car comes any week there will be a drawing on who goes 1,2,3. You will get to measure the new tire size (which will be all the same cold mark from factory if possible) before you go pick your scuffs from the “A” wall.
ENGINES (DMS will allow Crate Engines, LMSC 2012 Engines, and DMS “BUILT” Engines
1. CRATE ENGINES 1.The Following Crate Engines must be used as all supplied parts from factory manufacturer. May run aftermarket Distributor, valve covers. Chev 602 may run Chev 603 oil pan. 2.These engines are subject to teardown procedures and legalities is determined by tech committee. The staff at Dillon Motor Speedway has invested a lot of time and money to be “up to date” on these engines, therefore make sure the engine is legal or it will be caught. These engines may require different size carbs to equal horsepower between different model #.
GM #8602- — Ford Jr Motor –Ford Sr Motor GM #8603- — GM #8604 –Herrington Spec
2. These engines are designed to cut the cost of racing. Anyone found tampering with these engines will be fined up to $1000 for each offense and loss of championship points. 3. Crate Motor is a great application for Local Racing if the competitor will leave them alone. Run them as supplied from the factory to ensure legality. Contact Tech Official if you need clarification to this rule.
2. NASCAR Late Model Stock Car Engine with a Holley #7448 “350” CFM Carb at 3000lbs. The Nascar Late Model Stock with a Holley “450” Carb allowed at 3050 lbs.
This engine will be teched by the 2012 Nascar Rule book for the Engine Only.
3. DMS “Built” Straight Plug Head Motor- “500” Carb 1. Only stock standard production engines allowed. Chevrolet 350 cubic inch maximum, Ford 351 cubic inch, Chrysler 360 cubic inch plus overbore. 2. No polishing or coating inside of block. 3. Overbore of .060 + normal wear permitted. 4. Aftermarket solid steel connecting rods permitted. No polishing or machine work will be permitted. 5. Flat top 3 ring pistons permitted. Piston must not extend above top of block. 6. Crankshaft with stock stroke must be retained. No excessive grinding or machining, for balancing purposes only, subject to template inspection by tech official. Crankshaft must not be Knife-edged. Minimum weight 50# pounds for crankshaft. 7. Wet sump oil system only. Aftermarket valve covers allowed. Aftermarket pulleys allowed. 8. Enlarged oil pan allowed. Kick outs will not be permitted between the bolt holes flange and the top of the added sump.
HEADS 1. Stock OEM steel heads only. World Products Stock Replacement Head allowed with a 25 lb. weight penalty. See Weight. 2. No vortec heads on built motor, no angle plug heads allowed. 3. NO modifications, no porting or polishing. No grinding of any kind. 3 angle valve job ok as per Speedway rule. One cut below valve seat, to bottom of valve guide. Do not radius or blend bottom of cut below valve seat. 4. Chevrolet 70cc minimum; Ford (Clev) 68cc minimum; Ford (Win) 58cc 5. OEM valve size for cylinder head required. Steel valves required. Valve size maximum: Chevrolet 1.94 intake 1.50 exhaust Ford Cleveland 2.05 intake 1.65 exhaust Ford Windsor 1.89 intake 1.60 exhaust
CAM SHAFT 1. Hydraulic or flat tappet cam and OEM diameter lifters with a maximum lift of Chev .480, Ford .512 at valve with valve lash as ran in race. Hydraulic lifters will be measured at the retainer after replacing the hydraulic lifter with a solid lifter and zero lash.. 2. Any steel type timing chain allowed. 3. Any type valve springs and retainers allowed. Stud girdles are permitted. 4. Screw in studs and guide plates permitted with any ratio roller rocker arms allowed.
INTAKE and SPACER 1.GM performer 2101 current design, Ford M9424-P 2. No porting, polishing, or grinding will be permitted. Do not touch it. 3. Holley #7448 2bbl carbs allowed a one-piece solid aluminum spacer, ¾” thickness may be installed between intake manifold and carburetor. No coatings to intake or spacer. 4. Holley 4bbl carbs allowed a one piece solid aluminum spacer, 1” thickness four hole or open. 5. Holley #4412 carb 2bbl spacer must have 2 holes with max 1 11/16” openings. 6. Holes must be centered and cut perpendicular with the base of the carburetor. No tapers or bevels. 7. Only 2 gaskets, 1 per side, maximum thickness .065 will be permitted. 8. No adjustable or coated spacer will be permitted. No other modifications will be permitted. 9. All carburetors and spacer plates must meet speedway specifications.
Any car that does not conform to the above DMS Motor Rules may be allowed to compete with a weight and/or restrictor plate at the tech committee’s discretion. Tech Man decision is Final
CARBURETOR – The following carburetors will be eligible for competition. 1. Holley 2300 2bbl carburetor model #7448 “350” with a venturi size of 1 3/16”. 2. Holley 2300 2bbl carburetor model #4412 “500” with a venture size of 1 ½” 3. Holley HP80507-1 390 cfm four barrel model HP designed for crate engines
4. Holley “450” Carb is a combination of a Holley 500 Top and 350 bottom. A .3875 rings ok if used between the two. 450 Carbs Must use 350 aluminu spacer.
5. The New Ultra Holley 500 carb without the choke horn not allowed for competition. released in 2014.
1. No polishing, grinding or drilling holes will be permitted in the body of the carburetor. 2. Boosters may not be altered in any manner including size, shape or height. No Bevels. 3. Venturi area must not be altered in any manner. Casting ring must not be removed. 4. Base plate must not be altered in shape or size. 5. Stock butterflies must not be thinned or tapered. Idle holes may be drilled in butterflies. Screw ends may be cut even with shafts. 6. Throttle shafts must remain standard and must not be cut or thinned in any manner. 7. Any attempt to pull outside air other than through the venturi is not permitted
DMS “Built Straight Plug Head” engine must use: Holley #4412 2bbl carburetor “500” at 3100lbs DMS “Late Model Stock” engine must use Holley #7448 2bbl carburetor “350” at 3000lbs.
DMS “Late Model Stock” engine must use the Holley “450” 2bbl carburetor “450” at 3050lbs. GM#8602 Nascar 1.6 Crate engine may use: Holley #HP80507-1 “390” Four Barrel HP or Holley “650” Four Barrel at 3000lbs
GM#8603 Crate engine may use: Holley #HP80507-1 390 Four Barrel Model HP at 3000lbs. GM#8604 Nascar 1.6 Crate engine may use: Holley #7448 2 bbl carburetor up to “500” with 3100 lbs weight
GM#8604 Crate engine may use: Up to Holley “500″ 2 bbl carburetor with 3050 lbs weight. Ford# Jr Engine may use: – Up to Holley “390″ 4 bbl carburetor with 3050 lbs weight. Ford# Sr Engine may use: – Up to Holley “450” 2 bbl carburetor with 3100 lbs weight
Enforcer Engine may use: – Up to “350” Carb 2bbl carburetor with 3000 lbs weight
Any car that has a carb or spacer that does not pass tech will be allowed to race with a restictor plate ***Any clarification needed on the rules for the carburetor contact Technical Official***
WEIGHT 1. Base weight is 3000, 3050, and 3100 According to which motor listed (See Carb Section Above)
2. Max 55% left side max weight. 3. World Products Stock Replacement Head must add 25 lbs. to total weight. 4. Two speed, or “speed transmission” must add 50lbs. to total weight 5. All cars will be weighed with driver in a driving position. Cars may add fuel after race. 6. Weight of car must be on back of hood for tech purposes. 7. Any car competing with dislodged or lost weight may not add it back to make weight requirements after the race. 8. All lead weight must be added to chassis securely. 9. No tungsten allowed.
AMMENDMENTS 1. These rules are subject to amendments for competition when ample notice has been given by the speedway. Any car that does not conform to the above rules may be allowed to compete with a weight and/or restrictor plate at the tech committee’s discretion. 2. Speedway officials may use professional judgment for any rule or infractions for a competitive race program. 4. Rules for the race car are all the same. Different weight or Carbs are used to equal different motor combinations. It is a priority for Dillon Motor Speedway to make different engine combinations on an equal playing field. DMS and officials will do their best to make this happen.
Herrington, upgrade engines may 3000lbs with a 350 carb or with a 450 at 3100lbs.
****ANY RULES YOU DO NOT UNDERSTAND OR YOU NEED CLARIFICATION, PLEASE CONTACT SPEEDWAY OFFICALS. Email email@example.com or call the Tech Man Ronnie Barfield @ 843-319-9797 or Ron Barfield @ 843-496-4792.