X275 Radial Tire Series Shootout Information Page
FORMAT: This is an 1/8 mile heads-up class run on a .400 pro tree with a pro ladder. X275 is a qualified quick 8 field. Courtesy staging and autostart is in effect. There will also be another class called “The Shootout” for qualifiers #9-16, and it will be run on a pro ladder. This allows non-qualifiers to compete for additional points and a place to race.
Body: The car must retain its original appearance, profiles, and dimensions. Factory roof and quarter panels must be used. Aftermarket fiberglass replacement panels are limited to hood, front fenders, doors, decklids, and bumpers only. All hoods must be removable with quarter turn fasteners. All front ends must be of factory dimensions and cannot be stretched. Aftermarket wings and spoilers are permitted. Complete stock appearing front and rear bumpers are required. A hood must cover the entire induction system. Forward facing hood scoops are permitted.
Interior: Factory appearing dashboard, door panels, and driver seat is required. Full Carpet is required on floorboards. Bare inside frame of car cannot be exposed. Aftermarket steering column is permitted.
Windshield/Windows: OEM glass or lexan windows are permitted. No visible fasteners.
Chassis: Complete stock chassis and frame rails must be retained. Back-halved cars are not permitted. Front core support may be modified or removed. Aftermarket bolt-on replacement front K-members are allowed (if front shocks bolt to K-member then they must be in factory location). Mini tubs are allowed. Rear frame rails may be notched for clearance.
Engine: Maximum displacement for all engines is 588ci. Small blocks are allowed any deck height. GM Big Blocks are limited to a 10.2 deck height. Ford Big Blocks are limited to a 10.3 deck height. Mopar Big Blocks are limited to a 10.7 deck height.
Turbochargers: Turbochargers are measured at the inducer wheel diameter at the point where the leading edge of the compressor wheel meets the inlet housing. Any type intercooler is permitted. Cannot combine with nitrous oxide except on 2-rotor, 4-cylinder, and 6-cylinder cars.
Superchargers: Cog or gear driven superchargers are permitted. Any type intercooler is permitted. Cannot combine with nitrous oxide. Roots superchargers are limited to a 10-71. Centrifugal superchargers are permitted. Screw superchargers are not permitted.
Nitrous oxide: Small block is permitted to run any type multi-stage nitrous system (cars equipped with canted valve heads are limited to 2 nitrous stages). Big blocks are limited to a single stage nitrous system (A single stage fogger is permitted or if using a single plate then your limited to 1 fuel solenoid, 1 nitrous solenoid, and 1 purge solenoid, purge must exit engine compartment).
Transmission: Any style automatic transmission allowed. Converter driven planetary transmissions are prohibited. No clutchless manual transmission. Clutch assisted manual transmissions are permitted on naturally aspirated combinations only. Electric shifters or air shifters are prohibited.
Induction: Small Block combinations may run any type induction. Big Block combinations are limited to a single carburetor with cast intake.
Oiling system: Dry sumps are permitted on all cars.
Exhaust: Mufflers or inserts are required on all cars except for turbo cars. Exhaust may exit underneath car or out the front fenders.
Fuel: Gasoline only is permitted. Alcohol or E-85 or other derivatives is prohibited.
Street equipment: Functional headlights, taillights and brake lights required. All headlights, brake lights, marker lights, etc must be on car and not removed for any reason. All vehicles must be driven to the staging lanes, but may be towed back from their passes (do not tow to the staging lanes or you will be disqualified).
Suspension: Stock style suspension cars only (See weights below for penalty for aftermarket suspension). Four links are prohibited on all cars. Aftermarket direct replacement components such as: front control arms, rear control arms, front coil over shocks, and rear coil over shocks are permitted. Aftermarket rack and pinion steering allowed. Rear leaf springs, springs, shocks, and coil-overs may be moved to accommodate tire clearance, and do not need to be mounted in stock location. Bolt-on or welded sub-frame connectors, rear sway bars, are permitted on all cars. Wheelie bars are prohibited on all cars. Torque arms are only permitted on cars that were originally equipped from factory with it.
TIRES: All cars with power adder must compete on a Drag Radial type tire with the following sidewall designation 275/60/15. Naturally aspirated cars are permitted to run a 28.0” x 10.5” slick, no “W” tires permitted.
Minimum Weights: All minimum weights include the driver.
Naturally Aspirated (small block) 2700 lbs.
Naturally Aspirated (big block with standard deck height and conventional head) 3000 lbs.
Naturally Aspirated (big block with tall deck height and conventional head) 3100 lbs.
Naturally Aspirated (big block with standard height and big chief head) 3250 lbs.
Nitrous (small block) 3100 lbs.
Nitrous (big block with standard deck height and conventional head) 3250 lbs.
Nitrous (big block with tall deck height and conventional head) 3400 lbs.
Single YSI / F1A Supercharger (small block) 3100 lbs.
Single F1C Supercharger (small block) 3200 lbs.
Single F1R / Xi Supercharger (small block) 3300 lbs.
Single 76mm T6 Turbocharger (small block) 3100 lbs.
Single 80mm T6 Turbocharger (small block) 3200 lbs.
Single 85mm T6 Turbocharger (small block) 3300 lbs.
Single 88mm T6 Turbocharger with 85mm reducer (small block) 3350 lbs.
* Small Blocks with single stage nitrous system: deduct 100 lbs.
* Small Blocks (NOS only) with 23 degree Chevy heads, 20 degree Ford heads, and 18 degree Mopar heads: deduct 100 lbs.
* Non-Intercooled boosted cars: deduct 50 lbs.
* Aftermarket rear suspension (Ladder bar): add 50 lbs.
The rules will be in effect at the floowing tracks:
RULE REVISIONS & CHANGES
Tech reserves the right to accept or reject any car or driver. In order to maintain the most level playing field possible, MIR will constantly monitor the performance numbers of the numerous combinations in this class. From time to time, it may be necessary to adjust minimum weights to help promote class parity. These changes will be made if a particular combination is deemed too dominant. Racers should take this into consideration whenever they are constructing their cars. Also MIR reserves the right to change X275 back to 1/4 mile at any time during the season, with one week’s notice. Any rule revisions deemed necessary by MIR will be officially posted on www.mirdrag.com before the event in which they become effective. Be sure to check the website often for changes throughout the year.