Boyd Raceway Mini Stock Rules for 2025

1.Body: Any two or four door sedan, compact car only. No truck frames allowed. No front wheel drive or mid-engine cars allowed. No Rotary engines allowed. Aftermarket aluminum bodies are allowed. May use truck bodies on Pinto or Mustang chassis. Doors must be strapped, chained, welded securely. Must have a minimum of 3 door bars in front of drivers view. Spoilers allowed but not to exceed 6” in total height with 7” tall side boards. Skirting on the body is allowed with a minimum of 5” of ground clearance and securely mounted to the body. Hood scoops and holes in the hood are allowed. Rear filler panel across the back from quarter panel to quarter panel must be in place and no more than 10 in tall. Only exception is it can be removed for packing and mud cleaning. Front and rear tow chains must be in place and securely mounted. Numbers must be a minimum of 16” tall and contrasting from body color. No letters for numbers, must be numerical. If we can’t read them, you will be asked to fix them if not fixed you might not get scored properly.

2.Roll cage: Tech official will have authority to disallow any car with compromised structural integrity or poorly built cages. If they feel the car is unsafe you will not be allowed to compete until corrections are made to the car and passes inspection. All cars must have a minimum of 3 driver side door bars and 2 right side bars. All cars must have a minimum 6-point roll cage securely mounted in the vehicle. If welded to the floor pan in must be welded to a 6x6 steel plate. No more than 6” in from rocker panel seals. Bumpers may be a maximum of 2” diameter tubing with ends capped with no sharp edges. No wider than the middle of the tires. No cattle guard style front bumpers allowed. Nerf bars are allowed but must be securely mounted flush with the body, ends capped at a 45-degree angle. No to exceed 1x2 square tubing.

3.Engine: Inline 4-cylinder engine only. Fords to be 2300cc max + 0.60 overbore, Nissan & Toyota with aluminum head are restricted to 2200cc max + 0.60 overbore. Stock bore and stroke no stroking or de-stroking allowed. Max .060 oversized bore allowed. No aluminum heads except Toyotas & Nissans (see weight rule) Flat top pistons only no popup pistons allowed. No grinding, polishing or removal of casting numbers allowed on the outside of the block. No aftermarket racing blocks allowed. Racing oil pan allowed but must have a 1in inspection hole in easy access. If not equipped, you will be asked to remove the pan to inspect bottom end. Rotating Assembly: You must maintain a stroke of 3.13 +/- .010. Stock OEM replacement type production crankshafts allowed. Balancing rotating assembly is allowed but no lightening of crank shaft is allowed. No knife edging or lightening of rod throws. Rod and main journals must remain factory spec. H beam rods allowed. Chevy long rods allowed but not to exceed a 5.7 measurement. No aluminum or Titanium rods allowed. Pistons can be floated but must be flat top only.

4.Cylinder head: Any cast iron OEM production head allowed for that make and model. Must have unalters visible casting numbers. Solid or Hydraulic only no roller head allowed. No aluminum head except OEM Toyota and Nissan. Cam lift not to exceed 525 lift. This will be checked at the valve spring. Adjustable cam timing gear is allowed. Head may be flat milled only. May us head studs. No porting, polishing, grinding, gasket matching, acid porting allowed. Must have factory casting marks inside runners. No titanium valves are retainer’s magnet must stick. Cam towers may be braced for support. Valves no larger than 1.89 intake allowed. No modifying head in any fashion outside of factory specs period! Intakes: OEM intake only no aftermarket allowed or sideways carb mounted intake. Can weld outside plug water inlet or injector holes. No welding or epoxy inside the runners or plenum of the intake. No porting, polishing, gasket matching allowed. OEM castings must remain visible inside the intake. Can run D4, D9, or E1 style intake. Must have visible unaltered casting numbers. No powder coating or paint inside the intake.

5.Carburetor: Unaltered 2 BBL 500 CFM Holley 4412 or Holley 7448 350 CFM carb only. No 4 BBL carb, no fuel injection, turbo or super chargers allowed. No aerosol carb allowed, must have boosters. Must pass Holley Go No Go gauge. No modifications to the boosters or ventures allowed. Boosters may be safety wired in place. Fuel bowls must face forward. No grinding or polishing inside the Carb. Butterflies and throttle shafts cannot be narrowed or polished. NO HOLLEY XP carbs allowed. You may remove the choke plates but choke horn must remain unaltered. Max carb spacer height is 1 inch including gasket. Throttle return springs should be mounted in a safe manner. Throttle stop with 2 return springs is mandatory. Throttle rod/cable should be routed so the throttle will not hang open. Throttle pedal with toe return strap mandatory.

6.Chassis: Must have stock firewall and floor pans in stock location. From the seam up can be removed and replaced with aluminum. All holes in the firewall must be covered. Must have floor pans on both sides, repairs can be made to floor pan with a minimum of 16 Gauge steel. Must have a rear firewall sealing of fuel cell from the driver. Wheelbase must match left-right within +/- 1”. Can replace in front of the strut towers with a max of 2x3 rectangle tubing if it is in factory location. Rear can be replaced with 2x3 rectangle tubing. 2x3 rectangle may be substituted with 2 inch round tubing. Trunk floor may be removed. Leaf spring cars must retain the stock chassis all the way to the rear of the leaf spring mounts. Engine mounts may be modified or fabricated but must remain in O.E.M location. No tube chassis cars allowed. Subframes may be braced for strength.

7.Suspension: Front and rear suspension must be stock appearing and in OEM location. Trailing arms on the rear may be reinforced but must remain OEM lengths top and bottom. Aftermarket trailing arms may be used but must have rubber or neoprene bushings and OEM length. No hiem joints allowed or mono ball type bushings. All suspension components, springs, shocks, leaf spring mounts must be in stock location. With the following exceptions: A-arm front ends may shim the upper mounts to adjust caster/camber. Mounts can be moved to correct geometry but must remain factory mounts. Strut front ends may alter the top mounting points of the strut tower to adjust caster/camber. May use caster/camber plates, but must be welded. Strut towers may be braced, and support bar left/right is allowed. No weight jack bolts allowed on the front or rear of the car. Adjustable rear shackles are allowed and lowering blocks on leaf spring cars. Adjustable spring spacers are allowed on top of springs, racing spring is allowed. No other modifications are allowed outside factory spec. Shocks/Struts: Racing shocks and struts are allowed. Must be mounted in factory location with the exception of the rears. The upper mounts may be moved upward but must remain at the factory angle. The lower mounts must remain in stock location of the rear end. Hiem joint shocks will be allowed on the rears. No adjustable, Schrader valves, bulb shocks, air shocks allowed. One shock per corner of the car. Rebuildable shocks are allowed. No bump stops on shocks or struts will be allowed.

8.Rear End: Stock for make and model of car, 4 lug rear ends only on Pinto/Mustang. No Quick change or ford 9” rear ends. Locking of spider gears is allowed. No pan hard bars or adjustable trailing arms allowed. OEM only trailing arms. No Detroit locker, Posi-trac, limited slip rear ends allowed. Mini spool is allowed. Aftermarket replacement axle is allowed. May brace the housing for strength but cannot be narrowed. Must remain factory width. No hiem joints or spherical bushings allowed except shocks. OEM replacement type rear bushings only no Mono ball type bushings

9.Brake System: No aluminum or aftermarket calipers allowed. Aftermarket brake pads are allowed. Aftermarket pedal assembly is allowed. Four lug rotors only. Drum or disc brakes allowed. Must have at least 3 working brakes. Right front shut off allowed out of drivers reach. May remove caliper and rotor on right front only. No drilling holes in rotors allowed. Front to rear brake bias allowed.

10.Clutch/Transmission/Driveline: Stock appearing flywheels allowed. Mini clutch is allowed. Standard or automatic, no in/out boxes or direct drive allowed. No aftermarket transmissions allowed. Must have all gears in place and be able to go into all gears when asked. If the car must be push started from Staging Lane, you will start on the rear of the field regardless of line up. Minimum 2” diameter driveline no carbon fiber or aluminum drivelines. Must be painted white. Must have a 360-degree drive shaft safety loop 12” back from front u-joint securely mounted in place. Chains do not count as a safety loop. If not equipped properly you will be DQED.

11.Cooling System: Only one radiator is allowed securely mounted between the frame rails in front of the engine. Aluminum water radiator is allowed. Aluminum water pump is allowed. Overflow hose must be directed towards the ground in in a catch bottle. Racing pulleys allowed. No electric water pumps. No sprinkler systems in front of radiator allowed. Fan shrouds need to be securely mounted with no sharp edges.

12.Steering: OEM mounts in OEM location no modifying rack and pinion mounts. Quick release hubs are mandatory. Collapsible steering shaft recommended. Steering Quickeners are allowed. May use aftermarket power steering pumps. Weight: Minimum weight after the race with driver is 2200 lbs. Toyotas & Nissans must weight 2250 (or may be 2200 lbs if at least 50 lbs is added in front of the driver) due to aluminum heads. Cars can be weighted at any time. Fluids, parts, lead lost during the race cannot be added to make weight. If you are under weight, you will be DQED for that race. Check your weight on the track scales as this is what we go by not your scales at home. Weight must be painted white with car number on it. Securely mounted with ½ inch bolts per 25 lbs. If your weight comes off during a race you will be disqualified for that event. No ratchet straps, zip ties, hose clamps to secure weight. No weight in driver’s compartment. Can be mounted in the engine bay or rear trunk area only.

13.Tires/wheels: Racing wheels allowed. Any offset, up to 8in wide rims max can be 13, 14, 15 in diameter. Replacement of factory studs with 5/8 studs and 1” lug nuts is highly recommended. Wheel spacers are allowed but not to exceed a max on 1 inch worth of spacers per wheel. Bead locks are allowed. Racing tires are allowed but must durometer at 45. You may grind, groove, sipe your tires. No mud snow type tread tires allowed. Highway type tread only. No chemical treating of tires allowed. Max 10” tread width measured from outside of tread to outside of tread allowed. TIRES WILL BE CHECKED AND MUST DUROMETER A MINIMUM OF 45 AFTER THE MAIN EVENT.

14.Fuel System: No E85 or methanol fuel allowed. 110 octane race fuel max. Fuel scent is allowed. No fuel cool cans allowed. Electric fuel pump allowed but must have a on/off switch clearly marked and within race reach of the driver and track safety crews. Max 22 gal. fuel cell allowed. No plastic tanks or boat cans allowed. Vents must be equipped with rollover check valve. Aircraft style positive seal filler neck/cap or rollover flapper is required no tolerance! No part of the cell may be lower than protection bars. Must be mounted safely between the rear frame rails. Must be sealed off from the driver’s compartment. Cell must be covered and not exposed! If the fuel line passes through the drivers compartment it must be inside a tube, no open fuel lines.

15.Electrical System: Battery must be securely mounted in the trunk area and not in the driver’s compartment. Only one 12-volt battery is allowed no 16-volt batteries. MSD box is allowed. Standard or HEI distributor only. MELS distributor is allowed. No magneto distributors. Aftermarket coil and module is allowed. Master kill switch within easy reach of driver and safety crew mandatory.

16.Exhaust System: Header or stock exhaust allowed. Header may be wrapped, or powder coated. Must exit under the car. No exposed exhaust pipe inside the car, if exhaust passes through the fire wall it must be sealed off from the driver and safety crew. 4 into 1 and tri-y style allowed. Mufflers may be required by the track.

17.Safety: Must have a minimum of a 5 Point racing harness with 3” wide straps unless using the 2” wide head and neck restraint style belts. Securely mounted to the roll cage not eh floor pan. Recommended not to be over 3 years in age. Tracks discretion on older belts needing to be replaced. High back aluminum racing seat, containment highly recommended. Must have at least a right-side head support mounted to the seat and not the cage. Must have a 360-foam collar or head and neck restraint system and in place when coming across the scales. NO TOLORENCE you will be disqualified for that event if not in place. Approved full faced Snell 2000 or newer helmet no open-faced helmets allowed. Fire suit, gloves mandatory while on the track. Only exception will be packing but must have helmet and gloves on. Racing shoes are not required but highly recommended. Window net is not required but highly recommended. Fire extinguisher or fire suppression system is MANDATORY NO TOLORENCE!! If the track feels your car is not safe or your equipment isn’t safe you will not be allowed to run until those corrections are made. Race Receiver are always mandatory while on the track and must be present in tech and used properly. If it is not in place or hooked up, you will be disqualified for that event. No warnings will be issued on safety you will be disqualified and not allowed to compete till the issue is resolved. Take your safety serious!!

18.Protest: Any driver/registered car owner who wishes to protest a car may do so if the protesters car finishes in the top 4 of the A-main and the one being protested finishes ahead of them. The protesters car must first pass tech before being able to protest another car, if they are deemed illegal there is no protest. Protest fee and a written letter with which you are choosing to protest must be given to the tech official within 5 minutes of the checkered flag by either driver or his registered car owner. Only what is written will be inspected at that time nothing else. It is the track officials decision to DQ or not on anything found other than protested parts. During inspection there will be only the driver and 1 other person (mechanic or owner) to represent each team involved. If the car is found legal the protest fees will go to that driver minus track fee. If the driver is found illegal the money minus track fee will be refunded to the protester. If you are found illegal, you will lose pay for that event and points. Depending on the finding you will possibly loose point for the year and a possible 2-week suspension will be handed down. You must prove your car is legal before it will be allowed to compete again.

19.Protest/Claim Fees are as listed: Protest bottom end: $600.00 with $100.00 going to the track, $500.00 to winner of protest. Stroke to be measured while crank in the car with head removed. If no inspection hole motor to come out to inspect crankshaft. Top end protest: includes Heads, Carb, Intake, Bore and stroke from top end checked: $400.00 with $100.00 going to the track, $300.00 to the winner of the protest. Will remove head, check bore stroke, valve size, check for porting and polishing of head and intake. Protest bore and stroke: $250.00 with $50.00 going to the track, $200.00 to the winner of the protest. Removal of head and inspect just bore and stroke nothing else will be check or removed for this inspection. Anything found during tear down by officials is subject to DQ at the officials discretion. Shock claim: $100.00 per shock and swap with person claiming. Refusal to claim will result in loss of points and pay for the event. Once a person has been claimed within a season, he is no longer eligible to be claimed again that season. You must finish within 4 spots of the driver you are wishing to claim. This is for rear shocks only. General Rules: These rules are guidelines to try and even the playing field, sure some cars are faster than others but causing a seen isn’t the way to get your point across to anyone. Any car with 3 consecutive wins in a row is SUBJECT to having his head removed for bore and stroke to be check. No other people will be allowed during this process as it is NOT a protest. If you are not in the top 4 during tech, then STAY out of tech! Any person who is in tech that is NOT in the top 4 may be disqualified regardless of his finishing order and will lose points and pay for that event. If you are a crew member the driver you are associated with will be disqualified and lose of points and pay for that event. Only 2 people per car are allowed in the tech area and stay with YOUR CAR! We do not need people in tech causing a scene and telling people what to check. Any car can be teched before, during or after the races at the track’s digression regardless of the finishing order. Rules are subject to change at any time by the promotor or the track race director to engage in fair competition If you refuse tech, you will lose pay for that event and points for the season and get a 2-week suspension. You will also have to prove your car is legal to compete again for the issue you refused tech for. Top 4 from the heat and A Main will report to the scales for weight check. At this time officials will determine any other necessary action needed from these drivers. The track may pull random cars along with the top 4. If you need help understanding or need clarification, or just checking to see if something is legal, please reach out to the Boyd Raceway tech officials with questions.