I & II Car Classification Rules:
This is an unofficial transcription of Section 14 of the
Solo Rules. (Copyright Sports Car Club of America
2003; all rights reserved)
It is believed to be correct, but any questions should be referred to the
official rules as published by the SCCA. Order
your own copy here.
Changes since the
2002 Rules are shown like
Further changes from FasTrack are shown like
14. STREET PREPARED CATEGORY
Cars running in Street Prepared Category must have been series produced
with normal road touring equipment capable of being licensed for normal
road use in the United States, and normally sold and delivered through
the manufacturer's retail sales outlets in the United States. Cars not
specifically listed in
Stock or Street
Prepared Category classes in Appendix
A must have been produced in quantities of at least 1000 in a 12 month
period to be eligible for Street Prepared Category.
A vehicle may compete in Street Prepared Category if the preparation
of the vehicle has not exceeded the allowable modifications of Stock Category,
except as specified below. However, the distinction between different years/models
used in Stock Category does not apply in Street Prepared Category. Example:
Porsche 911 models that are listed on the same line are considered the
Cars listed as eligible in and prepared to the current national Improved
Touring rules are permitted to compete in their respective street prepared
classes. Logbooks are not required. Neither Street Prepared nor Improved
Touring cars are permitted to interchange preparation rules. Improved Touring
cars may use tires which are eligible under current IT rules even if they
are not eligible in Street Prepared.
Cars listed as eligible in and prepared to the current American Sedan
rules are permitted to compete in Class B Street Prepared. Logbooks are
not required. Neither Street Prepared nor American Sedan cars are permitted
to interchange preparation rules. American Sedan cars may use tires
which are eligible under current AS rules even if they are not eligible
in Street Prepared.
Cars listed as eligible in and prepared to the current national Touring
category rules are permitted to compete in their respective Street Prepared
classes. Neither Street Prepared nor Touring cars are permitted to
interchange preparation rules. Touring cars may use tires which are
eligible under current Touring rules even if they are not eligible in Street
While the rules of the Street Prepared Category have remained essentially
the same, the laws governing various aspects of street-driven vehicles
have changed over time. The original concept of this category as made up
predominantly of street-driven vehicles has been rendered inappropriate.
The SCCA does not encourage or condone the breaking of laws governing pollution
control systems or the alteration of street-driven vehicles contrary to
state and federal laws regarding their use. It continues to be the responsibility
of the individual to comply with such state and federal laws.
Specific vehicle classifications are located in Appendix
A of these rules.
14.1 Authorized Modifications
Refer to Appendix F for past clarifications
of these rules.
All Allowable modifications permitted in Stock Category are allowed.
Street Prepared vehicles may only be modified in excess of Stock Category
rules in the following ways. Any modification not specifically authorized
by the Stock Category or Street Prepared rules is prohibited. No unauthorized
modifications are permitted in order to accommodate authorized modifications
(i.e., non-stock hood scoops or holes necessary for carburetor clearance).
Structural modifications, such as the addition of members known as "jacking
rails", are not permitted unless specifically authorized herein.
Equipment and/or specifications may be exchanged between
different years and models of a vehicle if
(a) the item is standard on the year/model
from which it was taken,
(b) the years/models are listed on the same line of Appendix
A (Street Prepared Classes).
The updated/backdated part or the part to which it is to be attached
may not be altered, modified, machined or otherwise changed to facilitate
the updating/backdating allowance. The updating and/or backdating of engines,
transmissions or transaxles must be done as a unit; component parts of
these units may not be interchanged. Cars not listed in the Street
Prepared sections of Appendix A may not be updated/backdated until
approved by the SEB and published in SportsCar magazine.
Alternate computer control modules may be used whenever an equivalent change
to the conventional system is allowed. For example, alternate computer
module control of ignition settings or fuel injection is allowed. Direct
turbocharger boost control by alternate computer control is not, since
there is no equivalent mechanical allowance.
Air conditioning systems may be removed in whole or
in part. This rule should not be interpreted to allow modification of the
Fenders and bumpers
may be modified for tire clearance. Flares may be added
although tires may extend beyond the body work. Replacement of complete
flared fenders or quarter panels is prohibited.
Removal of factory trim is only permitted if the resultant configuration
is an allowed update or backdate.
Strut bars are permitted with all types of suspension. Strut bars may be
mounted only transversely across the car from upper right to upper left
suspension mounting point and from lower right to lower left suspension
mounting point. No other configuration is permitted. Additional holes may
be drilled for mounting bolts. Only bolt-on attachment is permitted.
Any fully padded and upholstered front seat may be used. This does not
permit the substitution of a passengers seat with a child or miniature
seat of any type. Any substituted passengers seat must be sufficiently
large and strong to be capable of adequately accommodating an adult, such
that it could be used as the driver's seat. The OEM
seat belts may be removed to facilitate the installation of alternate restraints
complying with safety requirements. Seat
tracks are considered part of the seat and may be substituted when an alternate
seat is installed.
Any steering wheel may be used. An alternate
wheel which replaces an airbag-equipped wheel is not required to have an
airbag. The alternate wheel is not required to have a horn button.
Spoilers and cosmetic trim pieces are permitted. Side skirts may not be
used. Spoilers must comply with the following subsections. The intent of
this allowance is to accommodate commonly available appearance kits, and
replicas thereof, which have no significant aerodynamic function at Solo
A spoiler may be added to the front of the car below the bumper. It may
not extend rearward beyond the front most part of the front wheel well
openings, and may not block normal grille or other openings, or obstruct
lights. Openings may not be used for the purpose of ducting air to the
radiator, or oil cooler, but they may allow air to flow through a permitted
oil cooler provided no ducting is used. The spoiler may not function
as a wing.
A spoiler may be added to the rear of the car provided it complies with
either of the following:
It is a production rear spoiler which is standard
or optional equipment of a U.S. model of the vehicle, or an exact replica
in an alternate material.
It is a non-production rear spoiler which is mounted to the rearmost portion
of the rear hatch, deck, or trunk lid. The spoiler may extend no more than
10 inches from the original bodywork in any direction. Alternatively, in
a hatchback, the spoiler may be mounted to the rear hatch lid at or near
the top of the hatch; in such a configuration the spoiler may extend no
more than 4 inches from the original bodywork in any direction. The spoiler
may be no wider than the bodywork, and it shall not protrude beyond the
overall perimeter of the bodywork as viewed from above. The use of endplates
is prohibited. Angle of attack is free. The spoiler may not function as
Roll bars and cages must comply with
Section 13.2.G in Stock category. Roll
cages must comply with the following:
The roll cage need not be removable.
It shall be bolted or welded to the car.
The cage shall attach to the car at no more
than 8 points, consisting of the basic cage with 6 attachment points, and
2 additional braces.
The forward part of the cage shall be mounted
to the floor of the vehicle. In addition, the 2 optional braces referred
to in (b) may be mounted, one on either side, from the forward section
of the cage to the firewall or front fender wells. No braces shall
pass through the front firewall.
The use of a fuel cell which complies with current
GCR requirements is permitted, provided all of the following additional
restrictions are met:
The capacity of the cell may differ by no more than 20% from that of the
The location of the cell may differ from that of the original tank by no
more than six inches in any direction.
The car meets all applicable Solo I safety standards, including those for
rollover protection and the installation of a fire extinguisher.
Fuel tank changes are permitted only as allowed under 14.1.C
and 14.2.H. No additional tanks or reservoirs may
Accelerator, brake, and clutch pedals may utilize substitute covers of
unrestricted origin, shape, and size, provided they meet the following
requirements: Covers must be securely attached, provide a non-slip surface,
not interfere with each other's operation, and must be deemed safe at Tech
Tires must meet the eligibility requirements for Stock Category with the
following exception: The list of non-eligible tires in Section
13.3.A is replaced with the following list, which may be altered at
any time by the SEB upon notification of membership.
No tire models are currently listed.
Wheels of any diameter, width, or offset may be used.
Wheel spacers are permitted. Wheel studs and knock-off wheel drive pegs
may be changed in length and diameter. Wheel bolts may be replaced with
studs and nuts.
14.5 Shock Absorbers
Shock absorber bump stops may be altered or removed.
On cars with lever-type shock absorbers, a tube-type shock absorber may
be added. If the lever-type shock serves no other purpose, it must be removed.
If the lever-type shock serves any other purpose, it must be retained.
Any shock absorbers may be used, provided they attach to the original mounting
points. The number of shock absorbers shall be the same as Stock. No shock
absorber may be capable of adjustment while the car is in motion, unless
fitted as orignal equipment. MacPherson strut equipped cars may substitute
struts, and/or may use any insert. This does not allow unauthorized changes
in suspension geometry or changes in attachment points (e.g., affecting
the position of the lower ball joint or spindle). It is intended
to allow the strut length changes needed to accommodate permitted modifications
which affect ride height and suspension travel. This allowance differs
from Improved Touring Allowance 12.1.4.d.5.d.1.
Any brake line, single or dual master cylinder, vacuum brake booster, brake
proportioning valves may be used. This does not allow
multiple separate cylinders, but does allow for any single, dual-circuit
cylinder. "Safety breakers" and units such as the "Brake Guard System"
are permitted. ABS braking systems may be disabled, but not removed;
brake boosters may be removed or added. Air ducts may be fitted to
the brakes, provided that they extend in a forward direction only, and
that no changes are made in the body/structure for their use. They
may serve no other purpose. Backing plates and dirt shields may be
modified or removed.
14.7 Anti-Roll (Sway) Bars
Any anti-sway bar is permitted. Bushing material, method of attachment,
and locating points are unrestricted. This does not
authorize removal of a welded-on part of a subframe toa ccommodate the
installation. Components such as anti-roll bars and strut housings which
serve dual purposes by also functioning as suspension locators may not
be modified in ways which change the suspension geometry or steering geometry,
and may not be installed in positions (e.g., upside down) other than that
of the original configuration.
Ride height may only be altered by suspension adjustments, the use of spacing
blocks, leaf spring shackles, torsion bar levers, or change or modification
of springs or coil spring perches. This does not allow the use of spacers
which alter suspension geometry, such as those between the hub carrier
and lower suspension arm. Springs must be of the same type as the original
(coil, leaf, torsion bar, etc.) and except as noted herein, must use the
original spring attachment points. Coil spring perches originally attached
to struts or shock absorber bodies may be changed or altered, and their
position may be adjustable. Spacers are allowed above or below the spring.
Suspension bump stops may be altered or
Suspension bushings may be replaced with bushings of
any materials (except metal) as long as they fit in the original location.
Offset bushings may be used. In a replacement bushing the amount of metal
relative to the amount of non-metallic material may not be increased. This
does not authorize a change in type of bushing (for example ball and socket
replacing a cylindrical bushing), or use of a bushing with an angled hole
whose direction differs from that of the original bushing. If the
Stock bushing accommodated multi-axis motion via compliance of the component
material(s), the replacement bushing may not be changed to accomodate such
motion via a change in bushing type, for example to a spherical bearing
or similar component involving internal moving parts. Pins or keys may
be used to prevent the rotation of alternate bushings, but may serve no
other purpose than that of retaining the bushing in the desired position. Differential
mount bushings are not suspension bushings and thus may not be substituted under
On vehicles with strut-type suspensions, adjustable camber plates may be
installed at the top of the strut, and the original upper mounting holes
may be slotted. The drilling of holes in order to perform the installation
is permitted but the center
clearance hole may not be modified. Any type of bearing or bushing may
be used in the adjustable camber plate attachment to the strut. The installation
may incorporate an alternate upper spring perch/seat and/or mounting block
(bearing mount). Any ride height change resulting from installation of
camber plates is allowed. Caster changes resulting from the use of
camber places are permitted
Addition or replacement of suspension stabilizers (linkage connecting axle
or De Dion to the chassis, which controls lateral suspension location) is
permitted. Traction bars or torque arms may be added or replaced. A panhard
rod may be added or replaced. Methods of attachment and attachment points
are unrestricted. This does not authorize removal of a welded-on part of
a subframe to accommodate installation. The
longitudinal member which GM refers to as a "torque arm" on 3rd and
4th generation Camaros, which controls differential movement, is covered by this
section and may be substituted or modified.
Changes in alignment parameters which result directly from the use of allowed
components are permitted. For example, the dimensional changes resulting
from the use of a cylindrical offset bushing which meets the restrictions
of 14.8.C are allowed, including those resulting from
a change in the pivoting action to
(a) about the mounting bolt, or
(b) about the bushing itself.
14.9 Electrical System
Any ignition setting adjustment or system may be used. An
original ignition sensor on a cam cover may be removed, and the hole
plugged. This may serve no other purpose.
The make, model number, and size of the battery may
be changed but not its voltage.
Relocation of the battery or batteries is permitted but not into the passenger
compartment. If the battery is relocated and the original battery tray
can be removed by simply unbolting it, the tray may be removed, or relocated
with the battery. Holes may be drilled for mounting or passage of
cables. Longer cables may be substituted to permit relocation. The number
of battery or batteries may not be changed from stock. The area behind
the rearmost seat is not considered to be within the passenger compartment.
Any starter, generator or alternator may be used in the original position.
This does not allow for the use of an alternator or generator having little
or no output. An alternator or generator must have an electrical output
equal to or greater than the original equipment unit. Any generator
or alternator pulley and belt of the same type as standard may be used
Wiring harnesses may not be removed in whole or in part. Wiring connectors
for emissions control devices are considered part of the harness, not part
of the emissions control system, and may not be removed.
14.10 Engine and Drive Train
Engines must retain standard type lubricating
system, but may have any oil pan (Accusump-type systems allowed), oil pump
and pickup, oil coolers, oil or fuel filters. Fuel filters must be of automotive
type and serve no other purpose. A permitted oil cooler may be positioned
in an opening in an allowed spoiler, provided no unauthorized modifications
are made in order to perform the installation.
Heat shields may be added.
Carburetors, fuel injection, intercoolers and intake manifolds are unrestricted.
Alternate throttle linkage and connections to facilitate installation of
allowed induction systems are permitted, but may serve no other purpose.
As utilized only on engines originally equipped with forced induction,
air-to-air heat exchangers (known as "intecoolers"), and radiators which
are part of air-to-liquid charge coolers, must be cooled only by the atmosphere.
The use of chilled liquids, ice, dry ice, refrigeration systems,
vaporized compressed gases, etc. is prohibited. If an induction
system item is allowed to be removed and its original mounting bracket
can be removed simply by unbolting it, the bracket may be removed as well.
Turbochargers may not be added, changed or modified. Turbocharger and supercharger
systems may only be updated/backdated with the accompanying engine unit.
No changes are allowed to waste gates, pressure sensors or their location,
and to other turbocharger or supercharger boost limiting systems.
This allowance does not permit changes to blow-off (pop-off) valves.
Devices known as "fuel cut defensers", and any modifications which alter
or defeat the fuel cutoff when it is activated by boost level, are not
Air cleaner(s) may be changed or removed, velocity stacks may be added.
Emission control devices may be modified or removed. This permits
the oil filler cap to be modified or substituted, but does not allow valve
covers or cam covers to be altered to install a breather or for any other
Intake water injection systems are allowed.
Fuel lines and pumps are unrestricted except as specified herein as long
as they do not pose a safety hazard. Fuel lines may be no larger than 1/2"
i.d. and may only connect to the original fuel tank or allowed fuel cell.
They may be no longer than necessary for reasonable and safe installation,
and may serve no other purpose. A single fuel feed line may be used. A
single fuel return line may be used, and a fitting for connecting it may
be added at or near the top of the fuel tank. This does not authorize "cool-cans".
Exhaust manifolds and muffler systems are free, except that they must be
quiet and terminate behind the driver. Exhaust heat shields may be removed.
Rear- and mid-engined cars without exhaust headers/manifold systems may
use any exhaust system that meets the requirements of 3.5. This permits
the removal of "heater boxes" in order to install headers on such cars.
One bolt-on torque suppression device may be used. A torque suppression
device attaches from the engine to the body, frame, or subframe in one
location, and controls engine movement at that location along a single
axis only. It may serve no other purpose.
Examples of permitted devices:
Examples of devices not permitted:
) a chain
) a rod with spherical bearings at each end.
Holes may be drilled to mount a torque suppression device. The installation
may not include the welding of any plate(s) to the motor
may it include multiple non-parallel links.
) one or more solid motor mounts
) any link which confines movement along more than one axis
) an engine mounting plate, or one or more plates rigidly bolted between
the engine and the frame.
This does not allow motor mount changes other than those which are
update/backdates of factory components.
The engine fan and fan shroud (unless it serves another purpose, e.g. as
an alternator/generator mount) may be removed, modified or replaced. Electrically
driven fans are allowed.
On two-cycle engines, the ports must be of standard
heights, size and configuration; crankcase volume and reed plates must
not be altered.
Any metal clutch assembly, metal
flywheel or metal torque converter
that uses the standard attachment to
the crankshaft may be used. Non-metallic friction
surfaces (e.g. clutch disks) may be used. Dowel pins may
be added. Minor repositioning of the clutch slave cylinder is allowed to
accommodate the alternate clutch, but the unit may not be relocated and
the repositioning may serve no other purpose. This
allowance does not permit the substitution of slave cylinders or the use
of non-original methods of clutch actuation (e.g. pull type vs. push type).
Any mechanical shift linkage may be used.
Limited slip differentials are permitted. This permits locked differentials,
either by design, welding, or mechanical means. Differential cases, internal
differential parts, and axle stubs may be machined as required for clearance
and installation to the extent that material may only be removed, not added,
and the exterior of the case may not be altered in any way. This machining
may serve no other purpose.
Cylinders may be rebored to .0472 in. over standard
bore and the appropriate standard oversize
piston may be substituted. Cast or forged, non-stock pistons of the same
dimensions and configuration as original equipment pistons may be used.
Additionally the replacement pistons must be of the same weight or greater
as the original equipment pistons. The .0472
in. limit is absolute, no additional tolerance is permitted to accommodate
wear. This allowance does not permit alternative ring
Rotating and reciprocating parts may be balanced but not lightened.
Intake and exhaust ports and manifold openings may be matched provided
no change is made more than one inch from the port/manifold interface.
Material may be removed to facilitate port matching,
but no material may be added.
Any transmission oil cooler may be used.
The engine cylinder head(s) may be milled only to that amount specified
in the manufacturer's workshop manual. If no amount is specified than a
maximum of 0.010 in. may be milled.
Axle/halfshaft and driveshaft retention/location devices may be installed
for safety reasons to control the motion of attached shafts upon the failure
of a coupling or universal joint. They may serve no other purpose.
Any accessory pulleys and belts of the same type
(e.g., V-belt, serpentine) as standard
may be used. This allowance applies to accessory pulleys only (e.g.,
alternator, water pump, power steering pump, and crankshaft drive pulleys).
It does not allow replacement, modification, or substitution of pulleys,
cogs, gears, or belts which are part of cam, layshaft, or ignition drive
or timing systems, etc. Supercharged cars are excluded from this
allowance. This does not permit replacement of integral pulley-damper/balancer
assemblies. Alternate pulley materials may be used. Idler
pulleys may be used for belt routing in place of items which the rules
specifically allow to be removed, such as smog pumps and air conditioning
compressors. They may serve no other purpose.
14.11 Out-of-Production Cars
Where a car is out of production and the manufacturer is either out of
business, stocks no parts or no longer has a required part, a part of any
origin but as similar as possible to the original may be substituted. The
entrant must be prepared to show documentary evidence that one of the three
circumstances above applies and that the substituted part is as similar
as possible under the circumstances. Substitute
parts which provide improvements in performance (e.g. superior gearing, lighter
weight, better camshaft profile, etc.) are not permitted under this allowance.
...Jerry Mouton || firstname.lastname@example.org
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