A- Modified

2024 A- MODIFIED RULES

NO CARBON FIBER. NO TITANIUM UNLESS OTHERWISE NOTED. NO BUMP STOPS. NO BUMP SPRINGS OR CHASSIS LIMITERS. NO TRACTION CONTROL DEVICE(S) OF ANY KIND.

CAR:

American made, factory production, 1970 or newer with parallel frame, rear wheel drive only. Minimum wheelbase 108”. Wheel base must be within 1” side to side.

WEIGHT: (Weight and left side percentage can be checked at ANY time before, during or after time trials and or racing events with the driver sitting in the normal driving position with helmet and fire suit.)

1. Minimum weight 2650 lbs.
2. 58% left side.
3. Tube clip cars must have 50 pounds in front of the flywheel of existing weight total.

CHASSIS

1. OEM stock for chassis clips or fabricated / tubular frames (must be approved by tech.)
2. Frames may not be widened or narrowed and must be able to support roll cage on both sides. Front cross members may be notched for radiator clearance only. No widening or fabricating of cross members. Must maintain stock measurement from cross member to A frame bolts.
3. Ride height minimum of 4” to body, frame and lead at all times. No pulling up on the car in the tech line.
4. MODIFIED TUBE CLIP. Must use stock lower A-Frames, steering box and idler arm. Must maintain 3-¼” from lower control arm bolts to bottom of cross member at all times. Lower mounts must be solid and non-adjustable. Must measure 17” – 1/4” tolerance from center bolt to center bolt on front side of lower control arm and 27” – ¼” tolerance. Any tube clip that doesn’t meet the specs will be deemed illegal.
6. Adjustable Idler arm allowed but MUST be mounted in stock location.

BODY:

1. Width 66 inches maximum length 120 inches maximum measured from front of door / back of engine block to the end of rear quarter at any point. 6” maximum body rake. Maximum 3” at door and 3” at quarter to get the 6” total. Body must be mounted straight on the chassis.

2. Firewalls can be aluminum and floorboards are to be made of steel only.
3. Fiberglass, aluminum or steel duplicates of body parts are permitted.
4. Full roof is mandatory and must completely cover halo bar. Maximum of 21 inch drip rails allowed.
5. Original roof line of vehicle should be maintained with a maximum of 1” drop rear to front.
6. No wings, ledges or other ground effects anywhere inside or outside the car.
7. Rear spoiler allowed 6“ x 60“ only. B- post side panel must be 6” asay from spoiler and half the height of spoiler.
8. Engine compartment will remain open, no side panels. Hood sides may have a maximum of 6” drop and be enclosed at the rear of the hood. Bodies should extend no further than back of the block.
NOTE: (passenger side of body must be no further forward then the rear of the block).
9. Lower rear quarter panel turns not to exceed 1 inch maximum with a maximum of 2-1”braces/supports. Quarter panel minimum height from top to bottom in the rear is 18”
10. Windshield must cover at least the driver side 1/8” lexan only. Rear window optional. If used must be lexan. 1/8” lexan only.
11. Maximum front nose width 43 1/2”

ENGINE:

1. 350 blocks with only two bolt or four bolt main blocks. 350 crank only. No studded blocks. .060 maximum overbore +.010, zero deck. No grinding in the block, screens OK. No overbore of lifter holes or repairs.
2. Heads stock open chamber head with stock valves and 100 lb seat pressure or EQ heads with IMCA hobby heads 76 cc 1.94 intake and 1.50 exhaust. Three angle valve job allowed. No bowl cutting, flat cut only 72 CC chambers, Diameter equals 1.250 maximum diameter. Stock rocker nuts and balls. World Products 4360KA heads Legal as well
3. Any flat top 2 or 4 eyebrow piston. Pistons may not stick out past the top of the block.
4. Rods 5.7 rod length (stock OEM) only for engines used. No aftermarket. No stroking or de-stroking of the engine allowed. No H-beam rods.
5. Crank-GM cast crank 48 lbs no knife edge. Balancing OK. Stock stroke and weight for the engine used.

6. Camshaft must be 450 maximum lift cam for open motor, with 500 cfm Holley 2 barrel (#4412 C or CT). NO solid or rollered cams. Must pass track gauges. Camshafts may be degreed. Stock rocker ratio for engine used. 1.5 GM steel rockers OEM lift will be checked out at rocker. No stud girdles. Screw in studs and poly locks OK. Stock OEM GM lifters. May run double roller chain, non-adjustable gear.
7. Ford or Mopar max lift camshafts shall be no longer than 480 theoretical lift at valve with .003 tolerance for Ford
8. Intake. Stock cast Quadra- jet or may run performer 2101 series intake. No bowtie, Corvette or boat intakes allowed. (Maximum 1” carb spacer.) NO airbox to carb or air cleaner
9. Distributor stock only GM. May use PN# MSD 8727CT Digital Soft-Touch HEI Rev Control Limiter only (must be mounted on right-hand side, visible to tech, out of reach of the driver). Chip rule (CRATE CARS) – 6300. BUILT MOTOR – NO CHIP RULE.
10. Push rods. stock diameter.
11. Water pump steel or aluminum. Stock harmonic balancer or OEM GM for engine used. Oil pan, valve cover and pulley builders option.
12. L88 flywheel OK 14 lb minimum
13. 602 steel head GM crate motor allowed with the following carburetor: 500 CFM Holley #4412 C or CT OR Holley 650 4150 Part # 80541-1 **Must have factory seals and by approved by Auburndale Speedway Tech prior to any qualifying, heats, or races – NO EXCEPTIONS
14. If 602 is not sealed, must run 500 cfm Holley. BUILT ENGINES MUST RUN 500 CFM HOLLEY ONLY!
15. 602 crate motors may run PAC PN#1210X valve springs. May shim to get to spring rule.
16. Built 350 or 602 crate motors. Per rules. ( 604 engines with 602 heads & intake NOT allowed). (No 603 crates ) N. 602 Crate may use aftermarket oil pan for ground clearance
17. Exhaust system must be mounted in such a way to direct spent fumes away from the cockpit of vehicle and must extend past frame rails and away from all areas of possible fuel spillage. All headers are allowed.
18. Rear of the engine (bell housing flange) must be mounted at least 72” forward from the centerline of the rear axle. Engine offset must be kept within the front stub. Engine offset maximum of 2” of centerline of front cross member. Crankshaft minimum height will be 11” from the ground to the center of the crankshaft. Must be wet sump only. No totally dry sump systems allowed. Wet systems must be operative.

Engine Blocks:

GM 350

Ford 302, 351

Chry. 318, 360

Heads:

GM 72cc min.

Chry. 64cc min.

Ford 60cc min.

Stock Diameter valve springs for heads used.

100 LB max seat pressure

TRANSMISSION:

1. Saginaw 3 speed or 4 speed, Muncie four-speed and turbo 350-400 automatic transmission with two forward and one reverse gear allowed. 10” inch minimum torque converters. No lock up converters. No five speed transmissions, No in/out boxes. No buttons or couplers. Must all be clutch operated with motor running and car still in position. Driver must be able to engage the car in gear and move forward, then backward at time of inspection. Clutch must be inside the bell housing. Must have all gears working and reverse. No light weight parts or straight cut gears.
2. Clutch size minimum 5 1/2 inches. Must add 50 lbs for any clutch smaller than 10” inches.
3. Stock OEM transmissions allowed, Power glide transmission allowed. NO RACING TRANNY’S ALLOWED.

DIFFERENTIAL:

1.9 inch floater or quick change. 10 or 12 bolt

2.Wide 5 hubs allowed with bolt on front adapters to stock spindle, stock lowers only. Must remain in the factory location.

3.No rear sway bar.

WHEELS & TIRES:

1.Racing wheels 15” x 8”. May run any combination of 2,3, or 4” offset wheels .

2.American Racer AR870 Tires (only).

3.No bleeders

ROLL CAGE:

1. Must consist of continuous hoops, not less than 1-¾” outside diameter must have a wall thickness of at least .095.
2. Must be frame mounted in at least 6 places.
3. Must consist of configuration of front and rear hoops connected by tubing on the sides or side hoops. Drivers heads must not protrude above the cage with helmet on and strapped in the driver seat. Roll cage must be securely supported and braced.
4. Protection of feet is mandatory. Bar across the back of the engine with vertical bars and rub rails or similar protection.
5. No brace bars forward of the cage may be higher than stock hood height.
6. Driver door bars must be as parallel with the ground as possible and located perpendicular to the driver so as to provide maximum protection for the driver without undue difficulty in getting into or out of the vehicle. Sidebars must be welded to the front and rear of metal cage members. Door bars less than .095” thickness should have 4 bars at least 1-1/2” diameter. Must have steel plate covering the driver’s door area.
7. Must have a five point harness with date specifications.
8. Window nets Mandatory

BUMPERS:

1. Must be used in both front and rear. Front bumper should be mounted frame end to frame end with bottom loop parallel to the ground. Should be made of 1-1/4” pipe and must be welded to support the car if lifted by a wrecker.
2. Rear bumpers, nerf bars, and bodies must not extend beyond width of the rear tires and must not contain any sharp edges.

3. Rear bumpers may be constructed of pipe, flat stock or Aluminum I-beam and must protect the fuel cell. Center bumpers front and rear must be 18” (plus or minus 2” from ground.
4.The bumper must be looped back into frame.