2016 STREET STOCK RULES

GENERAL RULES

1. All drivers must use a Raceceiver radio. Failure to have a working radio can result in disqualification.

2. Quick release racing safety belt and shoulder harness no older than three years must be installed.

3. Roll bars to be padded in driver’s area. Full windshield screen for driver protection strongly recommended.

4. Drivers are responsible for wearing an approved racing helmet and an approved fire retardant driver’s uniform and gloves.  Helmet no older than snell SA 2010.

5. A window net must be used.

6. Cars must weigh at least 3,100 pounds including driver after any event.

7. All weights to be securely fastened and painted white with car number painted on weight. Must be 1/2 inch or larger bolt to fasten weight and weight must be securely fastened.  No weight added above the deck or in driver’s compartment.

8. Driveshaft to be painted white.  Safe loop or chain around drive shaft must be in place.

9. All cars must be presentable to the public at all times and must be clearly identified with numbers 18 inches high.  No profanity or offensive sayings.

10. All electronic control devices are illegal, including traction control systems. Penalty will result in a $1,000 fine and all points removed for the season.  Big Diamond has a right to confiscate all or any illegal parts.

11. A working up to date fire extinguisher must be mounted in car.

Any North American made passenger cars from 1965 with a wheelbase of no less than 108 inches originally are allowed. Wheel base must remain stock except cars with a wheel base of more than 108 inches may be shortened to 108 inches with approval of speedway tech inspector on a case by case basis. No SUV’s, trucks, sports cars, convertibles or station wagons, or front wheel drive cars.

1. Body and frame must be same make, model and year. Interchanging permitted within “sister” cars only – i.e. Chevelle, Grand Prix and Monte Carlo; Camaro and Firebird etc. Prior approval for any interchanging of frame and body must obtained from a track technical official. Body must appear like a stock body in stock location on frame. Stock firewall mounts and stock body mounts may be removed but the firewall on the left side must be no more than 20 inches from the left front weight jacker and the firewall on the right side must be no more than 29 inches from the right front weight jacker. No chopping, channeling or modifying. All roof pillars must be stock in shape but can be outer skins only with support being provided by the roll cage (car must appear “stock”). All glass, lights, trim and other objects that may come loose should be removed.  Body panels must be bolted or welded,  Dzus buttoned bodies allowed. Rocker panels can be fabricated but must be steel and remain stock appearing.

2. Must be complete steel body or stock-appearing aluminum body. If using stock-appearing body, all lines and bends must match OEM body. Body must be in stock location and dimensions must remain as factory-produced; widening and/or narrowing of body will not be permitted.

3. Must have front and rear firewall. Full firewalls must be present between driver and engine compartment and driver and fuel cell. Aftermarket floor pans and firewalls must be constructed of steel no thinner than 20-gauge. If two front firewalls are used, the outer one will be the one from which all engine and seat location measurements will be taken. The inner one must have a 2-inch hole cut into it for measurement purposes.

4. Front and rear bumpers may be tubular and must be equipped with retention chains. Stock front bumper cover may be replaced with an aftermarket stock- appearing bumper cover of same manufacturer and comparable model; variations must be approved. Non-visible reinforcing pipe may be used behind bumper, but it must be securely fastened to the frame. Front and rear bumper covers must be present at the start of any event.  A bar may be used to protect the radiator as follows. A 3-piece design using a 1-1/4 inch pipe may be constructed which is no wider than the frame rails and no higher than 10 inches off the frame rails. A maximum of two bars may be attached to the top of the bumper from the protective hoop. Rear bracing of hoop is optional. Do not build a battering ram. Wrecker hook up point must be included. If bumper becomes loose or falls off during an event, car will be sent to pits.

5. If rub rails are used, they must be a single rail design.  May not extend past tread of any tire at any time.

6. No sharp edges or dead-end tubing.  Tubing must be bent into the frame inside or outside of the cars, this includes bumpers.

7. All doors must be welded or bolted shut.

INTERIOR

1. Seats and upholstery must be removed and a racing seat properly installed and firmly anchored. Driver’s seat may be no farther back than 60 inches measured from the vertical section of the firewall to the back of the seat cushion area.  No less than a 1/8″ plate of steel must be under seat and securely fastened.

2. Fuel tank must be replaced with a fuel cell which must be encased in an approved material and be secured with a minimum of two steel straps two inches wide.

3. Floor of trunk must be removed.

4. Battery to be securely fastened and may not be located in the driver’s compartment.

5. Roll bars must be a four-post design boxed frame, well braced, using at least 1-1/2 inch OD tubing with a wall thickness of .095-inch minimum, D.O.M. or chrome-moly recommended. The bars must be welded to the top of the frame and extend at least four inches above the driver’s head. Driver’s side must have a minimum of four protective side bars, three bars on the opposite side of the cage.  Two bars must run from the top of the cage to the rear frame section. No threaded pipe or pipe fittings in cage. Roll cage kits permitted.

6. All roll cage seams and joints must be fully welded.

7. The tunnel beside the driver’s seat and above the transmission and driveline cannot be more than 10 inches higher than the floor pan, must be bent at 90 degrees and extend to the right side of the roll cage.

8. Interior may be aluminum and may be boxed-in behind driver’s seat but must extend down to “X”-brace crossbar. No suspension components, including but not limited to adjusting mechanisms, can enter into the driver’s compartment

9. Entire area of floor under driver’s feet must be reinforced with at least 1/8- inch plate, steel or aluminum.

FRAME AND SUSPENSION

1. Frame must be the same make, model and year as body used with interchanging allowed only as discussed.  No aftermarket kit frames permitted. Front frame clips must retain OEM dimensions; no widening or narrowing of frames. No down-tube frames.

Leaf spring cars must use only OEM or OEM-type aftermarket steel leaf springs – no Chrysler springs on GM vehicles. Monoleaf or composite springs as well as sliders and weight jackers on leaf springs will not be permitted. Extended leaf spring shackles and adjustable lowering blocks are permitted.

2. Cars of uni-body construction must use a frame of eight inches in circumference (2”x2” box tubing) to tie front and rear frame rails together. Eight-inch circumference tubing is a minimum requirement.

3. All frames may be reinforced with round steel tubing to the front firewall and to the rear firewall but all frame components must remain in stock position. No lift arms or brake floaters. A panhard bar may be fitted but it must extend no farther than the center of the rear axle assembly, attach to the rear axle on the centerline of the axle tube and have only one mounting hole for each end.

3.1 Panhard Bar
A) A Rear panhard bar is optional
B) Bar must be constructed out of steel
C) Can be any width up to 42” max. Both ends must be inside of the inside edge of the rear frame rails (42” is the inside measurement of a stock GM frame at the rear end)

D) No springs or rubber bushings on panhard bar will be allowed

E) At rear end attachment, vertical centerline of panhard bar must be on vertical centerline of axle tube. No tolerance

F) At frame attachment, vertical centerline of panhard bar must be on vertical centerline of axle tube – 1” tolerance allowed

G) Bar can be mounted in front or behind the axle tube.

4.No part of chassis may be moved or relocated from its original position except where noted. Additional and unused suspension mounting holes in the frame intended for suspension component relocation will not be permitted and must be permanently filled.

5.UNIBODY CARS Original rear sub-frame can be replaced with square or rectangular tubing of at least .095” wall thickness and do not need to conform to the original shape or location but the leaf spring mounts must meet the following requirements: Wheelbase must be 108 inches on at least one side, leaf spring mounts must remain in their stock location, leaf springs must have a minimum outside-to-outside span of 46 inches (GM X-body) or 48 inches (GM F-body) and the spring mounts must have a front-to-rear center-to-center span of 55-1/2 inches.Rusted areas may be reinforced with a steel channel iron or tubing. All Rule 5 measurements are subject to a tolerance of one inch.

6. FOUR-LINK CARS The lower rear trailing arms must not exceed 22- 1/2 inches between bushing holes and must be mounted in the stock location on the differential and frame. The upper rear trailing arms may be shortened or lengthened to obtain the correct pinion angle. All 4 bars will be in place. Aftermarket bushings will be permitted. Slotted mounting holes and/or adjustable rod ends will not be permitted. Spring part of suspension must remain stock and be mounted in stock position on stock appearing fixtures. Rusted areas of stock fixtures may be replaced with other material but must remain in stock position.

7. Stock appearing rears and stock appearing Ford 9-inch rears permitted. No Grand National or floater rears permitted. Rear must be locked and must be mounted in stock position on stock appearing fixtures. Interchanging of rears permitted within manufacturer’s line, integral type for integral type or non-integral for non- integral. Any steel spool, replacement axles and C-clip eliminators permitted. No offset differentials or aluminum components allowed.

8. Stock spindles made by the manufacturer of car being used only. No interchanging. Front upper control arm may be a tubular aftermarket non-adjustable arm mounted on stock mounts. Steering quickeners are permitted.

9. The #1 cylinder spark plug hole on Chevrolet small-block V8s must be at least 1 inch forward of the left upper ball joint.

10. No double shocks.  Steel or aluminum body non adjustable shocks are permitted.  No shocks with shrader valves or reservoirs.  If stock spring pockets are rusted or damaged, they may be remanufactured but must closely resemble stock and remain in original stock position. Weight jacks permitted.

11. 12″ wide steel racing wheels only.  No wheel covers. Foam mud plugs are permitted.

12. Four wheel brakes must be in good working order at all times. Rear disc brakes are optional. Aftermarket master cylinder permitted. Master cylinder may be moved to inside driver’s compartment on inside of firewall. In-line proportioning valves permitted. No plastic brake lines.  Brake calipers and components must be stock for year, make, and model.

13. McPherson strut suspensions are not permitted.

ENGINES

1. Production V-8 engines limited to 358 cubic inches, (with a 4 cubic inch tolerance) and must be in chassis originally cataloged by manufacturer. Block must be a standard production cast iron block 350 cubic inches originally. No aluminum blocks. Stroke to remain stock 3.48″. Crankshaft must be factory production or stock dimension aftermarket steel or cast iron crank with stock stroke. No swapping of cranks. Crank may be turned to a maximum of .040-inch under. Chevrolet Bowtie and Ford SVO blocks permitted. Ford engines must use a cast iron or forged steel Ford production crankshaft having the stock stroke of a 351 Windsor engine and weighing at least 46 pounds. MOPAR high performance crank with part number P4120312 permitted. Minimum crankshaft weight is 46 pounds.

2. Connecting rods must be production items from a V8 engine less than 358 cubic inches. Any stock dimension steel connecting rod (no titanium) may be substituted. Modification to connecting rod length prohibited. Connecting rods, block and crank to be used in the same combination that the factory originally manufactured. Ford permitted to use 6 inch length connecting rod with approved SVO crank.

3. Flat top pistons only, zero deck (piston may not travel above block deck).

4. Cylinder head options:

Option I – Any factory production steel head originally having a minimum 60cc combustion chamber. No aluminum heads. No relocating of rocker arm studs.

Option II – For Chevrolet engines, Vortec/BowTie heads with casting number 25534421 (supersedes #25534351) and 25534445 (supersedes #25534371) and DART/World Products Sportsman II steel head with casting number of 1037 may be used. For Ford engines, the discontinued RHS ProAction heads with part numbers 35301, 35302 and 35303 are permitted as well as the World Products Windsor Sr. (casting number I-061) cast iron cylinder heads and Dart Iron Eagle heads (casting numbers 13310010, 13410010 & 13520020). The Ford “N” cylinder head, identified by a part number suffix “N351” or “N352” between two lower cylinder head bolt holes, is NOT permitted.

FOR ALL ENGINES: Must have a 60cc minimum combustion chamber, no relocating rocker arm studs and no porting or polishing except for matching ports in intake port of head only for a maximum depth of 3/4s of an inch. The lifter bores must remain stock. The valve seat area can be cleaned up using a maximum 80-degree grinding stone. No additional hand or machine work is permitted. Volume measurement of intake runner of head must remain stock with the exception of matching the intake ports to the intake manifold runners.

5.  Any Steel/SS Valve with 11/32” min valve stem. Max 2.08” Intake and 1.625” Exhaust. Any factory production head (installed as an assembly line option) that originally used a 5/16” stem diameter may keep that same diameter with the 2.08”/1.625” max head diameters listed. No titanium except for valve spring retainers & locks. Roller rocker permitted. Stock valve guide angle no relocating valve guides.

No dry sump systems. Oil system must be an internal pump wet sump style system and the oil must be stored in the oil pan (external pressure adjustment allowed). A single stage external belt driven oil pump may be used as long as the oil is drawn from the oil pan. No oil reservoir other than the oil pan attached to the engine allowed. No oil pressure accumulators allowed.

6. All factory identification numbers and or part numbers must remain on crankshaft, connecting rods and cylinder heads. If identification numbers or logos have been removed, the engine will be declared illegal. Main bearing caps must be iron or steel.

7. Limited to one two-barrel Holley 4412 gauge legal carburetor.

8. Any approved aluminum intake other than a Smoke Ram or Tunnel Ram. Intake height to be a maximum of 8 inches measured from the top of the carburetor bowl using a straight edge from the bowl to the #3 or #4 runner of the intake manifold.

9. Headers permitted; may be inside-the-rail, over-the-rail or 180-degree with collector and extend to or beyond firewall. “Tri-Y” style not permitted.

10. Starter must be in working condition at all times. Battery ignition only. Stock distributor with aftermarket components permitted, no modification to housing. No MSD ignition. Ford may use the Ford ignition box.

11. Gasoline only; no additives of any kind. No electric or belt-driven fuel pumps or pressurized fuel systems.

12. Stock clutch or stock appearing aftermarket clutch of stock diameter only.  No aluminum flywheels or pressure plate. No mufti-disc clutch or racing clutch. Must use a stamped steel blow proof bell housing with a 2×3-inch inspection hole located three inches from the transmission mounting surface for clutch inspection.

13. OEM manual transmission, automatic transmission, and aftermarket transmissions are permitted.  No 2 speed transmissions.  Transmissions must look, function, and appear as a stock GM transmission.  All gears must be in the transmission and in working order and be fully functional with a full operating clutch.  Automatics must use a working stock appearing torque converter.  All transmissions must retain all manufacturer’s identifying markings. If we cannot identify it, it will be considered illegal.

TIRES

Only an 11-inch Hoosier brand tire (either Hoosier Economy or Hoosier Spec) is permitted for competition. The largest tire permitted is the Hoosier Economy 11 inch tire measuring 16.75 inches from sidewall to sidewall with a 93 inch circumference. The tires must be a 1300/D-15 or harder compound. “Soaking” or any form of chemical tire treatment is illegal.

Just because it isn’t in the rule book, don’t assume it’s legal.  Feel free to call Jim Carey at 570-640-4171.

2016 STREET STOCK RULES

GENERAL RULES

1. All drivers must use a Raceceiver radio. Failure to have a working radio can result in disqualification.

2. Quick release racing safety belt and shoulder harness no older than three years must be installed.

3. Roll bars to be padded in driver’s area. Full windshield screen for driver protection strongly recommended.

4. Drivers are responsible for wearing an approved racing helmet and an approved fire retardant driver’s uniform and gloves.  Helmet no older than snell SA 2010.

5. A window net must be used.

6. Cars must weigh at least 3,100 pounds including driver after any event.

7. All weights to be securely fastened and painted white with car number painted on weight. Must be 1/2 inch or larger bolt to fasten weight and weight must be securely fastened.  No weight added above the deck or in driver’s compartment.

8. Driveshaft to be painted white.  Safe loop or chain around drive shaft must be in place.

9. All cars must be presentable to the public at all times and must be clearly identified with numbers 18 inches high.  No profanity or offensive sayings.

10. All electronic control devices are illegal, including traction control systems. Penalty will result in a $1,000 fine and all points removed for the season.  Big Diamond has a right to confiscate all or any illegal parts.

11. A working up to date fire extinguisher must be mounted in car.

Any North American made passenger cars from 1965 with a wheelbase of no less than 108 inches originally are allowed. Wheel base must remain stock except cars with a wheel base of more than 108 inches may be shortened to 108 inches with approval of speedway tech inspector on a case by case basis. No SUV’s, trucks, sports cars, convertibles or station wagons, or front wheel drive cars.

1. Body and frame must be same make, model and year. Interchanging permitted within “sister” cars only – i.e. Chevelle, Grand Prix and Monte Carlo; Camaro and Firebird etc. Prior approval for any interchanging of frame and body must obtained from a track technical official. Body must appear like a stock body in stock location on frame. Stock firewall mounts and stock body mounts may be removed but the firewall on the left side must be no more than 20 inches from the left front weight jacker and the firewall on the right side must be no more than 29 inches from the right front weight jacker. No chopping, channeling or modifying. All roof pillars must be stock in shape but can be outer skins only with support being provided by the roll cage (car must appear “stock”). All glass, lights, trim and other objects that may come loose should be removed.  Body panels must be bolted or welded,  Dzus buttoned bodies allowed. Rocker panels can be fabricated but must be steel and remain stock appearing.

2. Must be complete steel body or stock-appearing aluminum body. If using stock-appearing body, all lines and bends must match OEM body. Body must be in stock location and dimensions must remain as factory-produced; widening and/or narrowing of body will not be permitted.

3. Must have front and rear firewall. Full firewalls must be present between driver and engine compartment and driver and fuel cell. Aftermarket floor pans and firewalls must be constructed of steel no thinner than 20-gauge. If two front firewalls are used, the outer one will be the one from which all engine and seat location measurements will be taken. The inner one must have a 2-inch hole cut into it for measurement purposes.

4. Front and rear bumpers may be tubular and must be equipped with retention chains. Stock front bumper cover may be replaced with an aftermarket stock- appearing bumper cover of same manufacturer and comparable model; variations must be approved. Non-visible reinforcing pipe may be used behind bumper, but it must be securely fastened to the frame. Front and rear bumper covers must be present at the start of any event.  A bar may be used to protect the radiator as follows. A 3-piece design using a 1-1/4 inch pipe may be constructed which is no wider than the frame rails and no higher than 10 inches off the frame rails. A maximum of two bars may be attached to the top of the bumper from the protective hoop. Rear bracing of hoop is optional. Do not build a battering ram. Wrecker hook up point must be included. If bumper becomes loose or falls off during an event, car will be sent to pits.

5. If rub rails are used, they must be a single rail design.  May not extend past tread of any tire at any time.

6. No sharp edges or dead-end tubing.  Tubing must be bent into the frame inside or outside of the cars, this includes bumpers.

7. All doors must be welded or bolted shut.

INTERIOR

1. Seats and upholstery must be removed and a racing seat properly installed and firmly anchored. Driver’s seat may be no farther back than 60 inches measured from the vertical section of the firewall to the back of the seat cushion area.  No less than a 1/8″ plate of steel must be under seat and securely fastened.

2. Fuel tank must be replaced with a fuel cell which must be encased in an approved material and be secured with a minimum of two steel straps two inches wide.

3. Floor of trunk must be removed.

4. Battery to be securely fastened and may not be located in the driver’s compartment.

5. Roll bars must be a four-post design boxed frame, well braced, using at least 1-1/2 inch OD tubing with a wall thickness of .095-inch minimum, D.O.M. or chrome-moly recommended. The bars must be welded to the top of the frame and extend at least four inches above the driver’s head. Driver’s side must have a minimum of four protective side bars, three bars on the opposite side of the cage.  Two bars must run from the top of the cage to the rear frame section. No threaded pipe or pipe fittings in cage. Roll cage kits permitted.

6. All roll cage seams and joints must be fully welded.

7. The tunnel beside the driver’s seat and above the transmission and driveline cannot be more than 10 inches higher than the floor pan, must be bent at 90 degrees and extend to the right side of the roll cage.

8. Interior may be aluminum and may be boxed-in behind driver’s seat but must extend down to “X”-brace crossbar. No suspension components, including but not limited to adjusting mechanisms, can enter into the driver’s compartment

9. Entire area of floor under driver’s feet must be reinforced with at least 1/8- inch plate, steel or aluminum.

FRAME AND SUSPENSION

1. Frame must be the same make, model and year as body used with interchanging allowed only as discussed.  No aftermarket kit frames permitted. Front frame clips must retain OEM dimensions; no widening or narrowing of frames. No down-tube frames.

Leaf spring cars must use only OEM or OEM-type aftermarket steel leaf springs – no Chrysler springs on GM vehicles. Monoleaf or composite springs as well as sliders and weight jackers on leaf springs will not be permitted. Extended leaf spring shackles and adjustable lowering blocks are permitted.

2. Cars of uni-body construction must use a frame of eight inches in circumference (2”x2” box tubing) to tie front and rear frame rails together. Eight-inch circumference tubing is a minimum requirement.

3. All frames may be reinforced with round steel tubing to the front firewall and to the rear firewall but all frame components must remain in stock position. No lift arms or brake floaters. A panhard bar may be fitted but it must extend no farther than the center of the rear axle assembly, attach to the rear axle on the centerline of the axle tube and have only one mounting hole for each end.

3.1 Panhard Bar
A) A Rear panhard bar is optional
B) Bar must be constructed out of steel
C) Can be any width up to 42” max. Both ends must be inside of the inside edge of the rear frame rails (42” is the inside measurement of a stock GM frame at the rear end)

D) No springs or rubber bushings on panhard bar will be allowed

E) At rear end attachment, vertical centerline of panhard bar must be on vertical centerline of axle tube. No tolerance

F) At frame attachment, vertical centerline of panhard bar must be on vertical centerline of axle tube – 1” tolerance allowed

G) Bar can be mounted in front or behind the axle tube.

4.No part of chassis may be moved or relocated from its original position except where noted. Additional and unused suspension mounting holes in the frame intended for suspension component relocation will not be permitted and must be permanently filled.

5.UNIBODY CARS Original rear sub-frame can be replaced with square or rectangular tubing of at least .095” wall thickness and do not need to conform to the original shape or location but the leaf spring mounts must meet the following requirements: Wheelbase must be 108 inches on at least one side, leaf spring mounts must remain in their stock location, leaf springs must have a minimum outside-to-outside span of 46 inches (GM X-body) or 48 inches (GM F-body) and the spring mounts must have a front-to-rear center-to-center span of 55-1/2 inches.Rusted areas may be reinforced with a steel channel iron or tubing. All Rule 5 measurements are subject to a tolerance of one inch.

6. FOUR-LINK CARS The lower rear trailing arms must not exceed 22- 1/2 inches between bushing holes and must be mounted in the stock location on the differential and frame. The upper rear trailing arms may be shortened or lengthened to obtain the correct pinion angle. All 4 bars will be in place. Aftermarket bushings will be permitted. Slotted mounting holes and/or adjustable rod ends will not be permitted. Spring part of suspension must remain stock and be mounted in stock position on stock appearing fixtures. Rusted areas of stock fixtures may be replaced with other material but must remain in stock position.

7. Stock appearing rears and stock appearing Ford 9-inch rears permitted. No Grand National or floater rears permitted. Rear must be locked and must be mounted in stock position on stock appearing fixtures. Interchanging of rears permitted within manufacturer’s line, integral type for integral type or non-integral for non- integral. Any steel spool, replacement axles and C-clip eliminators permitted. No offset differentials or aluminum components allowed.

8. Stock spindles made by the manufacturer of car being used only. No interchanging. Front upper control arm may be a tubular aftermarket non-adjustable arm mounted on stock mounts. Steering quickeners are permitted.

9. The #1 cylinder spark plug hole on Chevrolet small-block V8s must be at least 1 inch forward of the left upper ball joint.

10. No double shocks.  Steel or aluminum body non adjustable shocks are permitted.  No shocks with shrader valves or reservoirs.  If stock spring pockets are rusted or damaged, they may be remanufactured but must closely resemble stock and remain in original stock position. Weight jacks permitted.

11. 12″ wide steel racing wheels only.  No wheel covers. Foam mud plugs are permitted.

12. Four wheel brakes must be in good working order at all times. Rear disc brakes are optional. Aftermarket master cylinder permitted. Master cylinder may be moved to inside driver’s compartment on inside of firewall. In-line proportioning valves permitted. No plastic brake lines.  Brake calipers and components must be stock for year, make, and model.

13. McPherson strut suspensions are not permitted.

ENGINES

1. Production V-8 engines limited to 358 cubic inches, (with a 4 cubic inch tolerance) and must be in chassis originally cataloged by manufacturer. Block must be a standard production cast iron block 350 cubic inches originally. No aluminum blocks. Stroke to remain stock 3.48″. Crankshaft must be factory production or stock dimension aftermarket steel or cast iron crank with stock stroke. No swapping of cranks. Crank may be turned to a maximum of .040-inch under. Chevrolet Bowtie and Ford SVO blocks permitted. Ford engines must use a cast iron or forged steel Ford production crankshaft having the stock stroke of a 351 Windsor engine and weighing at least 46 pounds. MOPAR high performance crank with part number P4120312 permitted. Minimum crankshaft weight is 46 pounds.

2. Connecting rods must be production items from a V8 engine less than 358 cubic inches. Any stock dimension steel connecting rod (no titanium) may be substituted. Modification to connecting rod length prohibited. Connecting rods, block and crank to be used in the same combination that the factory originally manufactured. Ford permitted to use 6 inch length connecting rod with approved SVO crank.

3. Flat top pistons only, zero deck (piston may not travel above block deck).

4. Cylinder head options:

Option I – Any factory production steel head originally having a minimum 60cc combustion chamber. No aluminum heads. No relocating of rocker arm studs.

Option II – For Chevrolet engines, Vortec/BowTie heads with casting number 25534421 (supersedes #25534351) and 25534445 (supersedes #25534371) and DART/World Products Sportsman II steel head with casting number of 1037 may be used. For Ford engines, the discontinued RHS ProAction heads with part numbers 35301, 35302 and 35303 are permitted as well as the World Products Windsor Sr. (casting number I-061) cast iron cylinder heads and Dart Iron Eagle heads (casting numbers 13310010, 13410010 & 13520020). The Ford “N” cylinder head, identified by a part number suffix “N351” or “N352” between two lower cylinder head bolt holes, is NOT permitted.

FOR ALL ENGINES: Must have a 60cc minimum combustion chamber, no relocating rocker arm studs and no porting or polishing except for matching ports in intake port of head only for a maximum depth of 3/4s of an inch. The lifter bores must remain stock. The valve seat area can be cleaned up using a maximum 80-degree grinding stone. No additional hand or machine work is permitted. Volume measurement of intake runner of head must remain stock with the exception of matching the intake ports to the intake manifold runners.

5.  Any Steel/SS Valve with 11/32” min valve stem. Max 2.08” Intake and 1.625” Exhaust. Any factory production head (installed as an assembly line option) that originally used a 5/16” stem diameter may keep that same diameter with the 2.08”/1.625” max head diameters listed. No titanium except for valve spring retainers & locks. Roller rocker permitted. Stock valve guide angle no relocating valve guides.

No dry sump systems. Oil system must be an internal pump wet sump style system and the oil must be stored in the oil pan (external pressure adjustment allowed). A single stage external belt driven oil pump may be used as long as the oil is drawn from the oil pan. No oil reservoir other than the oil pan attached to the engine allowed. No oil pressure accumulators allowed.

6. All factory identification numbers and or part numbers must remain on crankshaft, connecting rods and cylinder heads. If identification numbers or logos have been removed, the engine will be declared illegal. Main bearing caps must be iron or steel.

7. Limited to one two-barrel Holley 4412 gauge legal carburetor.

8. Any approved aluminum intake other than a Smoke Ram or Tunnel Ram. Intake height to be a maximum of 8 inches measured from the top of the carburetor bowl using a straight edge from the bowl to the #3 or #4 runner of the intake manifold.

9. Headers permitted; may be inside-the-rail, over-the-rail or 180-degree with collector and extend to or beyond firewall. “Tri-Y” style not permitted.

10. Starter must be in working condition at all times. Battery ignition only. Stock distributor with aftermarket components permitted, no modification to housing. No MSD ignition. Ford may use the Ford ignition box.

11. Gasoline only; no additives of any kind. No electric or belt-driven fuel pumps or pressurized fuel systems.

12. Stock clutch or stock appearing aftermarket clutch of stock diameter only.  No aluminum flywheels or pressure plate. No mufti-disc clutch or racing clutch. Must use a stamped steel blow proof bell housing with a 2×3-inch inspection hole located three inches from the transmission mounting surface for clutch inspection.

13. OEM manual transmission, automatic transmission, and aftermarket transmissions are permitted.  No 2 speed transmissions.  Transmissions must look, function, and appear as a stock GM transmission.  All gears must be in the transmission and in working order and be fully functional with a full operating clutch.  Automatics must use a working stock appearing torque converter.  All transmissions must retain all manufacturer’s identifying markings. If we cannot identify it, it will be considered illegal.

TIRES

Only an 11-inch Hoosier brand tire (either Hoosier Economy or Hoosier Spec) is permitted for competition. The largest tire permitted is the Hoosier Economy 11 inch tire measuring 16.75 inches from sidewall to sidewall with a 93 inch circumference. The tires must be a 1300/D-15 or harder compound. “Soaking” or any form of chemical tire treatment is illegal.