ANA MELERO,

of the vehicle. No permitted or alternate component or modification shall additionally perform a prohibited function. 4.4 Requests for alteration, modification, and/or substitution of any specification or component shall be submitted to the Club for approval. The approval process will include, but not be limited to, an analysis of cost, availability, performance impact, rule enforceability, and competitor input.

5 Authorized Modifications

The following modifications are authorized on all Production Category cars. Modifications shall not be made unless specifically authorized herein.

5.1 Engine

5.1.1 Component Modification

5.1.1.1 Original and alternate components of the engine may be lightened, balanced, and modified by any mechanical or chemical means, provided that it is always possible to identify required components as original. Such means include, but are not limited to, shot peening, glass beading, heat treatment or hardening, plating, and milling or otherwise tooling.

5.1.1.2 No material or mechanical extension may be added to any required original component unless specifically authorized by these rules. Any repair performed to a required original component shall clearly serve no other prohibited function.

5.1.2 Induction System

5.1.2.1 The standard or approved optional carburetor(s) may be modified. The number, model, type, throttle plate and shaft location, and bore diameter (as measured at the throttle plate) shall remain as specified. All inducted air shall pass through the venturi(s) of said carburetor(s). All carburetors with restricted venturi(s) must retain such venturi(s) in the original location within the carburetor. Cars without an SCCA® spec sheet may use any carb which mounts to the original mounting bolt pattern size using the original mounting hardware and intake manifold without modifying either. Any car which cannot mount a Weber 32/36 mounting bolt pattern size carb will be allowed to use an adapter no greater than 3/8" thick to adapt the manifold to the Weber mounting size. Cars with an SCCA® spec sheet may follow either the spec sheet or use the above statement, however, you cannot exceed carburetor size listed on spec sheet if doing so. A car with a transverse mounted engine may use an adapter no greater than 1 1/4" in order to rotate the carb from it’s original mounting orientation.

5.1.2.2 Fuel injection is prohibited on Production Category cars unless specifically authorized on vehicle specification line. Approved cars utilizing fuel injection shall use the factory manifold and throttle body. Throttle body bore size shall remain stock. Manifold and throttle body may be ported and polished. The manifold may be cut apart to facilitate this work. When such disassembly is rewelded, the external dimensions of the manifold shall remain unchanged. The number of injections shall remain the same as stock and their relative mounting position and injection point shall be unchanged. The fuel injection system is unrestricted except that the original type (electrical, mechanical, etc.) shall be maintained. External throttle linkage to the standard fuel injection may be modified or changed.

5.1.2.3 Extensions to, or the addition of material to the exterior of the carburetor body is prohibited. Floats shall not be removed or altered to produce a float less type carburetor.

5.1.2.4 All carburetors shall retain their standard method of fuel distribution. Utilization or modification of components that effect an annular discharge configuration is prohibited.

5.1.2.5 Air cleaners, velocity stacks, and air supply ducts and boxes are unrestricted provided no modification of the body or chassis of the car is required to accommodate their use.

5.1.2.6 Original or approved alternate intake manifold(s) may be ported and polished. It/they may be cut apart to facilitate this work. When such disassembly is rewelded, the external dimensions of the manifold shall remain unchanged.

5.1.2.7 Where a single down-draft carburetor is listed as an alternate on a vehicle's specification page, an adapter may be used to fit the alternate carburetor to the original intake manifold. The adapter may be restricted to dimensions given on the vehicle's specification page.

5.1.2.8 No portion of any intake manifold may extend into the intake ports of the cylinder head or rotary-engine end plate. All alternate intake manifolds shall be capable of attachment without modification of the cylinder head or end plate. Port-to-port balance pipes or tubes in all intake manifolds may be plugged or restricted.

5.1.2.9 Any linkage may be used between the throttle and the accelerator pedal. Two spring-loaded systems of positive throttle closure are strongly recommended.

5.1.3 Fuel System

5.1.3.1 Any fuel pumps, lines, filters, and pressure regulators may be used, provided no component serves any fuel cooling purpose.

5.1.3.2 Fuel lines that pass through the driver/passenger compartment shall be metal braided or entirely covered and protected with a metal cover. If a mechanical pump is replaced, a blanking plate may be used to cover the original mounting point.

5.1.4 Emission Equipment

5.1.4.1 Exhaust emission control air pumps, associated lines, nozzles and other mechanical electrical emission devices shall be removed. When EGR air nozzles are removed from a cylinder head, the resultant holes shall be completely plugged.

5.1.5 Cylinder Head

5.1.5.1 The original or a specified alternate cylinder head shall be used. Porting, polishing, and machining within the limits of Production Car Rule 5.1.1.1. are unrestricted. Any valve guides and valve seats may be used. (See vehicle sheets for specific restriction.) On engines which are restricted to Improved Touring cylinder head preparation, the cylinder head and/or valve train may be machined for clearance to install an alternate camshaft. 5.1.5.2 Compression ratio may be increased by means of milling the head, and it may be machined to utilize O-

rings to replace or supplement a cylinder head gasket. 5.1.6 Camshaft and Valve Gear

5.1.6.1 Any camshaft(s) and lifters/cam followers may be used. Lifters/cam followers shall be of the same type and diameter as original.

5.1.6.2 Cam timing chains, gears, belts, and sprockets are unrestricted provided that they are of the same type, quantity, and dimensions as originally fitted. Double-row chains may be substituted for single row.

5.1.6.3 A timing chain/belt tensioner may be added to those engines not originally so equipped, provided that it acts upon that portion of the chain/belt that travels from the crank drive to the first cam sprocket/gear. The timing chain cover may be modified to facilitate its use. Adjustable cam timing sprockets are permitted.

5.1.6.4 Any metal valves meeting the specified head diameter may be used. Any valve springs of the same type as originally fitted may be used. Valve retainers, keepers, seals and adjustment shims are unrestricted.

5.1.6.5 Pushrods, valve rocker arms, shafts and attendant assemblies are unrestricted.

5.1.7 Block

5.1.7.1 The block may be rebored no more than 1.2mm (.0472 in) larger than the maximum dimension given on the specification page for that make, model, and displacement. A cylinder block from any model from the same manufacturer which is of the same material and dimensionally identical throughout, except for non-critical bosses, is permitted.

5.1.7.2 Cylinder sleeves may be fitted to the block for repair purposes if they serve no other prohibited function. Oil passages may be enlarged, restricted, or plugged.

5.1.7.3 Any crankshaft main bearing caps and any additional main bearing cap bolts may be used, provided that no material is added to the block for their use.

5.1.7.4 The compression ratio may be increased by means of milling the block, and it may be machined to utilize O-rings to replace or supplement a cylinder head gasket.

5.1.7.5 The block may be machined for the purpose of adding or substituting crankshaft oil seal(s) and related attachment devices.

5.1.8 Pistons and Rods

5.1.8.1 Pistons, pins, clips and/or pin retainers and piston O-rings are unrestricted. Pistons shall be constructed of metal.

5.1.8.2 Alternate ferrous connecting rods of the same center-to-center dimensions as original are permitted. 5.1.9 Crank and Flywheel

5.1.9.1 Alternate crankshafts are permitted. Such a component shall be listed on the vehicle's specification page, shall be constructed of ferrous material, and shall have the same stroke and bearing journal diameters as the original crankshaft. It shall retain the original angles of the crank throws and the original firing order.

5.1.9.2 In all cars, the original direction of crankshaft rotation shall be maintained. 5.1.9.3 The use of any external crankshaft vibration dampener is permitted.

5.1.9.4 Any flywheel of the same diameter as the original may be used, provided it attaches to the standard or alternate crankshaft at the original location. Additional fasteners and dowel pins may be added. The diameter of the flywheel includes the diameter of the ring gear. Cars which are allowed a specific alternate transmission may use the stock size flywheel for that alternate transmission.

5.1.9.5 Any modification or substitution of the clutch assembly and its dimensions is permitted. Carbon clutches are prohibited.

5.1.10 Oiling System

5.1.10.1 Any mechanically-driven oil pumps may be used, including a dry sump system. The dry tank shall be mounted within the body work. If said tank is mounted in the driver/passenger compartment, it shall be isolated from the driver by means of a metal bulkhead or additional container that retains any spillage or leakage. 5.1.10.2 The use of any oil pan/sump, scrapers, baffles, windage trays, oil pickup(s), pressure

accumulator/"Accusump" and oil filter(s) is permitted. Filter and accumulator location is unrestricted, but they shall be securely mounted within the bodywork.

5.1.10.3 Oil filters mounted in the driver/passenger compartment shall comply with the isolation specifications of Production Car Rule 5.1.10.1., above. Any oil lines may be used. If such lines run through the driver/passenger compartment, they shall meet the safety specifications for fuel lines in Production Car Rule 5.1.3., above. 5.1.10.4 The installation of any type of vent or breather on the engine is permitted. Crankcase, oiling system,

breather, or catch tank evacuation systems that are in any way connected to the exhaust system are prohibited. 5.1.11 Starter/Ignition/Electrical System

5.1.11.1 The use of any driver-operated electric starter is permitted, provided it is installed in the same general location as the original starter.

5.1.11.2 Any ignition system and ignition components may be used, provided no functional modification of the engine is required for their use. Magneto systems are prohibited. If a distributor is removed, a blanking plate or breather may be fitted in its place. Adjustments from the passenger compartment during competition is prohibited. (The intent of this change is not to eliminate dual ignition systems, nor to restrict driver selection between multiple ignition systems, i.e. crank-triggered and points, of cars so equipped).

5.1.11.3 The original generator or alternator may be completely removed or replaced by any unit fitted to the same location and utilizing the same drive system as the original.

5.1.11.4 Any make, size, or voltage of battery is permitted. Battery location is unrestricted within the bodywork. If moved from the manufacturers original location, it must be in a nonconductive marine type container or equivalent. The hot terminal must be insulated on all cars. All batteries (onboard power supplies) shall be attached securely to the frame or chassis in such a way as to insure that the battery will remain in place. 5.1.11.5 The wiring harness may be altered or replaced. Electrical accessories (horn, signal lights, etc.) may be

altered, replaced, or removed. 5.1.12 Exhaust System

5.1.12.1 Any exhaust manifold and exhaust system may be used. All exhaust systems shall meet the specifications of GCR Automobiles - General Regulations section 9.3.7., "Exhaust Systems". Refer to Section 5.9.1.16., of these rules for permitted body modifications for exhaust systems.

5.1.13 Other Engine Components

such as seals, bearings, water pumps, etc., is permitted. Electrically-driven water pumps are prohibited. Fasteners may be substituted.

5.1.13.2 Bushings may be installed where none are fitted as standard, provided they are concentric, and that the centerline of the bushed part is not changed. The addition of alignment dowels is permitted.

5.1.13.3 Gaskets may be replaced with others of unrestricted origin.

5.1.13.4 Alternator/generator, crankshaft, and water pump pulleys may be altered or replaced by others of unrestricted origin.

5.1.13.5 One or more engine torque suppressors (steady rods) may be fitted. Original torque suppressors may be altered or replaced.

5.1.13.6 Motor mounts of alternate design and/or material may be used, but there shall be no change to the engine's fore-and-aft or vertical location. Transverse-engine vehicles may rotate the engine about the crankshaft centerline to align axles/CV joints. On rear engine/rear drive cars the engine/drivetrain may be relocated vertically upward, to a maximum of 1" (one inch), to allow alignment of suspension and driveline components. No other engine rotation or relocation is permitted on any car.

5.2 Engine, Rotary Piston(only)