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2013 Hobby Stock 3.28.13


2013 Hobby Stock Rules

BODY & FRAME:

American made passenger cars and trucks minimum of 108 inch wheelbase.  Any measurement less than 107.5 inch will be considered illegal. Wheel base may not be altered to change the original wheelbase.   Novas allowed.  Camaros 

not allowed.  All bodies must be steel factory appearing.  Any steel factory style OEM body is permitted, and must have factory hood, trunk, roof, fenders, doors, and quarter panels. No after-market bodies, no stock car style bodies, 

no aluminum bodies or body panels. No holes allowed in the hood therefore no working hood scoops. Note:1981-1988 Performance Bodies street stock Monte Carlo steel body is the only after-market body allowed. All bodies must be 

proportionate to the year and make of frame. Frame must remain square and to factory specs.  Interchange of non-stock packages will be closely scrutinized and subject to track official approval. Firewalls must be complete, from 

fender to fender, top to bottom.  Steel firewall cannot be further back than 40 inches from top (front) of sector bolts in frame. Cut area must be closed with 20 ga. steel and welded.   Stock floor pan must extend from front firewall 

to rear firewall.  If decking is installed driver compartment must be enclosed with 20 ga. steel, with complete interior window level decking (may be aluminum).  If compartment enclosed, and decking in place, rear firewall may be 

removed, floor pan must remain from front firewall to no less than 25 inches forward of rear axle centerline and must fully extend from left rocker panel to right rocker panel. Driver must be on left side of drive shaft.  Driver must have 

an unobstructed view at all times.  B pillar must remain but can be replaced with plastic or aluminum, in stock location.  No narrowing of frame allowed.  Frame may be altered only forward of steering gear box. On the rear, frame may 

be altered no less than 8” behind original upper shock mount. Fender well may be altered or removed.  No part of driver's seat shall be less than 30 inches forward of left rear axle centerline.

 

 

STEERING AND SUSPENSION:

Quick release steering wheels are permitted.  Cast iron steering box only.  Quick steer boxes are permitted.  Steering gear must be factory stock for make and model of frame.  All steering parts must be OEM type. Racing type shock 

absorbers are allowed, but must be stock mount type, in stock OEM location.  Rubber control arm bushings only on the rear, mono-ball types are not allowed. No drilling of rubber bushings. Stock lower control arms are required.  

Lower control arms must be in stock factory location and be stock for make and model of frame being used.  Control arm mounts may be removed for frame repair, but must be reinstalled in stock location.  Upper control arms must 

match IMCA type jig or sample control arm used for technical inspection.  Stock upper control arms may be used. Steel bushings are allowed for front upper and lower control arms only.  No offset bushings, no mono balls, no bearing 

type.  


SPRINGS:  Racing springs are allowed. Rear coil spring must not extend through the stock spring bucket.  Coil spring spacers are allowed. No jack bolts.  Maximum coil spring length 13”.  Racing springs may be used.  Adjustable spring 

bucket allowed on front and rear in stock location.   Steel leaf springs only. May be after-market, but no adjustable lowering blocks.  Any steel non-jack bolt type leaf spring shackles are allowed  Multi-hole shackles may be used.  No 

sliders.


WHEELS AND TIRES:Eight inch wide steel wheels mandatory.  One bead lock is allowed, on the right rear wheel only. Tires may be siped and/or grooved.  Any brand DOT radial tire is allowed.  Allowable sizes are 225/60, 235/60, 

245/60, 255/60 and 275/60, A/R KK704 or Hossier IMCA stamped G60.  Any tire designed or intended for racing other than those listed above is not permitted.

 

WEIGHT:  3200 LBS minimum at the end of the race with driver. If car lost any component part, or parts, during race, it will be weighed without those parts replaced.  


ENGINE LOCATION:  Number one cylinder spark plug must be even with, or forward of, the upper control arm ball joint.

           

ENGINE:
Cast iron block only.  Maximum engine size is 364 cubic inch.  Aftermarket stock appearing connecting rods and crankshafts are allowed. No lightweight cranks allowed.  No knife edge, no bull nosing, undercut or drilling of second or 

third rod journal throws allowed.  Polishing of connecting rod beams not allowed.  Stock appearing rods only.  Rods must be 5.7” rods only.  3.48 stroke only. Connecting rods may be of press fit or  floating pins.  No 400 cid blocks 

allowed.  Flat top or dished pistons only; four valve reliefs per piston required. Pocket size must be symmetrical in size.  No modifications allowed. No cam shaft gear drives allowed.  Unaltered, stock cast iron intake manifold required.  

No "marine", "bowtie" nor aluminum manifold allowed.  Compression rule 175 psi with 5 starter hits.  Oil pan 1” inspection plug between the 2nd and 3rd bolt holes from the front of the motor on the drivers side is recommended to avoid 

oil pan removal.  No obstruction inside of pan.

  1. CRATE ENGINE: GM PART # 88958602
  2. THESE ENGINES ARE SEALED AT THE INTAKE MANIFOLD, CYLINDER HEADS, FRONT COVER AND OIL PAN WITH SPECIAL TWIST OFF BOLT HEADS ORIGINALLY INSTALLED BY GM. 
  3. A 602 GM Crate motor can be deemed legal in the Hobby Class provided one of the following options are used:
    1.  Motor still has the original GM installed twist-off bolts in all locations.
    2. If the motor is to be rebuilt, it must be done by an authorized Nesmith Crate Motor Rebuilder and have the Nesmith seals installed by same at the completion of the rebuild and must be able to provide original receipt.
    3. Golden Triangle Raceway Park is requiring their special seals be installed while in the presence of the designated GTRP tech personnel prior to racing at GTRP.  If the 602 is new, it must be brought to the designated location for inspection and seals installed by GTRP inspector prior to removing the motor from the shipping container.  If you are bringing a rebuilt 602 to race at GTRP, you must complete section B above and then have GTRP seals installed prior to being declared ilegible to race. 
    4. BGS will accept any of the three methods listed above as legal requirements.

 

  1. CRATE ENGINE MUST NOT BE ALTERED, MODIFIED OR CHANGED FROM FACTORY SPECS.
  2. ANY SEALS THAT HAVE BEEN REMOVED AND/OR TAMPERED WITH WILL MAKE THE ENGINE ILLEGAL AND NOT ELIGIBLE FOR COMPETITION UNTIL ONE OF THE METHODS FOUND IN PARAGRAPH 3 HAVE BEEN MET.
  3. 1ST OFFENSE PENALTY FOR TAMPERING WITH SEALS, MODIFYING ANY INTERNAL ENGINE PARTS, CHANGING ANY STOCK PARTS AS DELIVERED SEALED FROM THE FACTORY WILL BE SUBJECT TO A SUSPENSION OF 90 DAYS FROM THE DATE OF INFRACTION.  2ND OFFENSE PENALTY WILL BE DETERMINED BY TRACK OFFICIALS AND MAY BE UP TO 365 DAYS SUSPENSION.
  4. NO VACUUM PUMPS.
  5. CARB—One Holley 4412 that must pass go or nogo gauge.

MAY USE ONE CARB SPACER (2 INCH-ONE PIECE WITH .040 TOLERANCE MAX.) AND TWO STANDARD PAPER GASKETS. (Max. TOTAL .070 inch thick).   ONE GASKET ALLOWED BETWEEN INTAKE AND SPACER AND THE OTHER BETWEEN SPACER AND CARB.

ANY ELECTRONIC DISTRIBUTOR-TYPE IGNITION SYSTEM.  (NO CRANK TRIGGERED, DISTRIBUTORLESS MULTI-COIL, OR MAGNETO IGNITION SYSTEMS ALLOWED).


                       

FORD ENGINE:

289, 302 or351 CID blocks only.  Any cast iron OEM head is allowed.  No after market or Boss head is allowed.  Must follow same machining procedures shown below, for GM heads.

 

HEADS:
Any open chamber cast iron OEM factory production straight plug cylinder head is permitted, with the exception of factory high performance type heads.  Most common allowable casting numbers are ..882, ..487,..993 and ..441.   No 

closed chamber heads allowed, such as ….461 and …465.  Valve size is limited to 1.94 inch intake and 1.50 inch exhaust for GM.   GM 305 heads are the only exception allowed, however, intake valve cannot exceed 1.84 inch 

diameter, and exhaust valve cannot exceed 1.50 inch diameter.  OEM or stock appearing after market rocker arms allowed.  No roller tip rocker arms or rocker arm stud girdles allowed.  After market style rocker arm lock nuts are 

permitted.  Push rod guide plates are permitted.   Rocker arm studs may be pinned or screw in type.  Any single valve spring, with damper, is allowed.  Heads may be flat milled; no angle milling.  No porting or polishing.  Any work done 

in the valve bowl area must be done with a 360 degree cut, with the valve guide as the center point.

CAMSHAFT:

Hydraulic cam and lifters only.  Roller lifters of any type are not permitted. Camshaft lobe lift not to exceed .300  Maximum valve life allowed is .450” measured at the valve.

 

IGNITION:

Stock type H.E.I. type ignition. Any ignition module is allowed. Any cap mounted coil. MSD style ignition is not permitted. One 12 volt battery allowed.

EXHAUST:

Any street or racing header allowed, except stepped tube and/or 180 degree types.  Must be chassis design type.  Collector may not extend beyond back of driver’s seat.

 

CARBURETOR AND FUEL:

No fuel injection.  GM must run Holley 4412 2 bbl. Ford must run Holley 4412 2 bbl.  No modifications or machine work allowed except choke horn may be milled off on 4412. Racing fuel is allowed but with no performance 

additives or fragrances. Carburetor must pass go/no go gauge.

 

TRANSMISSION:

Any OEM automatic transmission (powerglide or turbo 350) is allowed.  Transmission must be stock and have full working torque converter.  Torque converter must be minimum of 10 inch.  No direct drives, valved pumps or bleeder 

style valve bodies.  All forward and reverse gears must be in working order for all automatics, except Powerglides, which may have either one or both forward gears, along with neutral and reverse in working order.  Transmission 

coolers are allowed, but may not be mounted exposed in driver’s compartment.

 

Manual transmission must be OEM stock cast iron three or four speed allowed, with all gears in working order.  No Bert, Brinn nor internal clutch style transmission is permitted.  Minimum 10.5 inch clutch, pressure plate, full size and 

weight flywheel required.  Aluminum flywheel not permitted.    No mini clutch or direct drive permitted.  Ram couplers not allowed. Manual transmission must have bell housing a minimum of .250 inch thick steel covering top and 

minimum of each side of clutch assembly (also referred to as blow-proof bell housing). No quick change transmission or transmission adapter for gear change is allowed. Car must be self starting, and have working neutral, reverse and 

all forward gears, as noted.


REARENDS:

Rear-ends must be OEM for make and model of frame, with stock length upper and lower control arms for that frame required.  Any gear ratio which can be installed with altering of rear-end housing is allowed.  8.5 inch may replace 

7.5 inch.   Axles must be locked together at all times, with mini spool or weld.  No limited slip, Detroit locker nor full spool allowed.

 

BRAKES:

Minimum of three wheel brakes required.  No adjustable proportioning valve allowed.  After market brake pedal assembly is allowed, with one master cylinder permitted.  Rear disc brakes allowed, with steel components and a single 

piston caliper used.



ROLL CAGE:

All roll bar uprights must be a minimum of 1½ inch OD, .095 inch wall tubing.  Must have minimum of three bars on driver’s side and two bars on passenger side.  It is recommended all welding be done by a trained and competent 

welder.  Door bars to be of same description tubing as uprights.   A hoop is allowed from front up rights to front of car, on both sides.  Bumpers can be stock bumper shell covering tubing.  Bumper must cover no less than frame horn 

to frame horn, front and rear of car.  One nerf bar per side of car is permitted.  Nerf bars cannot extend forward of front edge of door panel nor rearward of front edge of rear wheel opening.  Nerf bars cannot extend out past outer 

line of tires, at any time.  No sharp edges permitted on nerf bars or bumpers.

 

SPOILERS:

Spoiler max height is 6 inches and must be attached to the rear of trunk only.

 

SAFETY:

All cars must have an aluminum racing seat securely attached to roll cage.  Five point seat belt harness, with current dates, is required.  All cars must have a window net that is used any time car is in competition.  All cares must 

have a battery disconnect that is in clear view of safety personnel and is easily accessible.