Below is the updated rules for the infamous X275 radial class. As usual it is bound to ruffle some feathers and cause some issues. Please review these new rules and make sure you are up to date on them. We at E3xtreme had an enlightening conversation with one the the class front runners this evening and can't wait to see what they have in store very soon. If there are any more updates to this we will let you know.
2016 X275 Rules updated 5/17/16
This is a 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 auto-start 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. (At larger events 2 – 16 or 3 – 8 or 3 -16 car fields or all-run format may be used) THIS IS A SINGLE POWER ADDER CLASS ONLY!
All NHRA/IHRA and Local Track Safety rules apply for driver and car, including the use of an oil retention device or engine diaper.
Any material used for the purpose of adding to a car's total weight must be permanently attached to the car's structure and must not extend in front of or behind the rear of the car's body. No liquid or loose ballast permitted (i.e., water, sandbags, rock, shot bags, metal weights, etc.)Removable weight must be securely mounted to the frame or frame structure by a minimum of two 1/2 inch diameter steel bolts per 100 pounds, or one 3/8 steel bolt per 5 pounds; all other weight bars, pucks etc. Must use a minimum 2 - 1/2 inch diameter SAE grade 8 bolts for attachment per 100 pounds. Maximum ballast may not exceed 550lbs.
The car must retain its original appearance, profiles, and dimensions. Factory roof and quarter panels must be used. Aftermarket fiberglass and/or carbon fiber replacement panels are limited to hood, front fenders, doors, deck-lids, and bumpers only. All front ends must be of factory dimensions and cannot be lengthened and must meet all NHRA/IHRA height. (See ground clearance note below). Any beam tripping devices forward of the bumper are prohibited. (Track tech official will have final say) Aftermarket wings and spoilers are permitted. Complete stock appearing front and rear bumpers are required. A hood must be used: scoop or hood must cover the entire induction system. Forward facing hood scoops/ turbo or supercharger inlets are permitted.
Minimum 3 inches from front of car to 12 inches behind centerline of front axle, 2 inches for remainder of car, except oil pan, oil retention device, and headers.
Factory appearing dashboard, door panels, and driver seat is required. Full Carpet is required on floorboards including transmission tunnel. Factory floor pan on driver and passenger side required from firewall to rear of door jamb. Transmission tunnel maybe removable and must be metal. Bare inside frame of car cannot be exposed. Aftermarket steering column is permitted.
OEM glass or Lexan windows are permitted.
Complete stock chassis and frame rails must be retained from motor plate/shock tower to behind the rear wheel opening. Back-halved cars are not permitted. Front core support may be modified or removed. Aftermarket bolt-on replacement front K-members/sub frames are allowed (if front shocks bolt to K-member then they must be in factory location, only Chevy II or Dart permitted strut conversion). Shock tower can be notched or trimmed but must be in factory location, verifiable by the factory sheet metal being retained between frame rail and top of tower. Mini tubs are allowed. Rear frame rails may be notched for clearance and must be in the factory location. Factory wheelbase must be maintained. (+ or – 1 inch)
Maximum displacement for all engines is 588ci. Small blocks are allowed any deck height but must retain stock bore spacing. Big block allowed the following deck heights but must retain stock bore spacing. 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. (Cylinder head specs and list for BB Nitrous Combos attached)(Billet SB/BB blocks permitted with cast head only and 50 lbs.)
Single turbocharger limited to 88 mm maximum. (Garrett GTX55-88, Exile ETR-88, or = Forced Induction, Comp, Bullseye - mid frame or current (2013) Gen II Pro Mod MF88, PTE LF85 or LF88 turbos only). Turbocharger size will be verified by measuring the housing bore at the leading edge of the impeller wheel and must maintain the contour of the compressor housing. (Stepped or Clipped compressor wheel prohibited) Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 4.765 inches on MID FRAME turbos. Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 5.56 inches on LARGE FRAME turbos. The maximum diameter of the housing bore at the leading edge of the wheel may not exceed 2 mm more than the maximum allowable turbocharger size permitted. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type of air to air or water to air intercooler permitted. Turbochargers w/nitrous-oxide prohibited except on 2-rotor, 4 cylinder, and inline 6 cylinder engines.
Cog or gear driven superchargers are permitted, must meet all factory inlet, outlet, and internal housing dimensions. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type intercooler is permitted. Supercharger cannot be combined with nitrous oxide. Roots superchargers are limited to a 10-71. Centrifugal superchargers are permitted. Screw superchargers are not permitted.
Small block is permitted to run any type multi-stage nitrous systems. Big blocks are limited to a single stage fogger (2 nitrous solenoids, no limit on fuel solenoids) and two bottles are 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. Big Block & Small block nitrous are permitted water injection. All EFI Big Blocks will only be allowed 2 nitrous solenoids for a dry nitrous system and will only have 1 line per nozzle/per cylinder. (Using both sides of the fogger nozzle on a dry EFI NOS BB combo are prohibited)(Cold nitrous systems permitted on big block combo and permitted on small block combo) All lines on big block combo must be visible and continuous from bottle to wye without interruption.
Any factory style automatic transmission allowed. OEM factory style manual transmission allowed. Bruno-Lenco transmissions are prohibited. Aftermarket clutch-less manual transmission and clutch assisted manual transmissions are permitted on naturally aspirated and nitrous small block combinations only. Electric shifters or air shifters are permitted.
Small Block combinations may run any type induction. Big Block combinations are limited to a dedicated single opening cast intake with a single carb or a single 4150 or 4500 series throttle body. (4 blade, dual blade or single blade throttle body permitted).
Dry sump oiling systems are permitted on all cars
Mufflers or inserts are required on all cars except for turbo cars. Exhaust may exit underneath car or out the front fenders but must not affect timing or staging beams.
Gasoline only is permitted. Alcohol/E85 permitted on roots blown/V6/Inline-6/4cyl applications. Alcohol or E-85 or other derivatives is prohibited on all other combinations. Meth injection prohibited. Water injection permitted on SB NOS combos only.
Functional headlights, taillights and brake lights required. All headlights, brake lights, etc. must be on car and not removed for any reason. All vehicles may be towed back from their passes.
Stock style or ladder bar suspension cars only. Aftermarket 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. (see notes below) Upper and Lower control arms must be mounted in the factory chassis locations -S Box permitted.
All cars with power adder must compete on a Drag Radial type tire with the following sidewall designation 275/60/15. Naturally aspirated combos are permitted to run a 28.0” x 10.5” slick, no “W” tires permitted.
MINIMUM BASE WEIGHTS (SVA applies to 23* GM 20* Ford 18* Mopar 15* LS heads)
*All minimum base weights include the driver.
All weights set with 3754X Pro Tire, add 50 lbs. for lock up converter. Billet block permitted with cast head/intake only add 50 lbs.
* NA Small Block 2300 lbs. (28 x 10 slick or 28 x 10 Pro Bracket Radial and any transmission permitted)
* NA Big Block up to 648 cu in – stock bore space any cylinder head-any intake 2600 lbs.
-- deduct 100 lbs. for under 588 cu inch (28 x 10 slick or 28 x 10 Pro Bracket Radial and any transmission permitted)
* Nitrous Small Block 2600 lbs.
--*Small Blocks (NOS & NA) with single 4150 carb/throttle body: deduct 50 lbs.
--*Small Block (NOS) with any plate system: deduct 50 lbs.
(does not apply if used in conjunction with a fogger)
--*Small Blocks (NOS & NA) with 23 degree Chevy heads, 20 degree Ford heads, and 18 degree Mopar heads: deduct 100 lbs. Raised Runners -75 lbs.
--*Small Block (NOS only) 18 -10 degree valve angle inline head: deduct 50 lbs.
--*Small Block (NOS only) cast Tunnel Ram/Sheet Metal 2 carbs – 2 throttle bodies: add 50 lbs.
-- add 50 lbs. for 28 x 10 Pro Bracket Radial
* Nitrous Big Block 2850 lbs.
-- 9.801 and up deck add 50 lbs.
-- no additional weight for traditional style cross bar plate.
-- deduct 50 lbs. for single nitrous solenoid cross bar plate/carb combo.
-- plenum style nitrous plate add 50 lbs.
-- fogger system add 150 lbs. (no line or bottle restrictions)
-- add 50 lbs. for 28 x 10 Pro Bracket Radial
* Turbo Small Block 3050 lbs.
-- base weight set with cast SVA inline/mod motor and LF88/GTX-55-88/PTE PM Gen II 85 or (billet headed 80mm x 130 on M1)
-- deduct 400 lbs. for GT47-76 with cast SVA (M1 permitted)
-- deduct 350 lbs. for GT47-80 with cast SVA (M1 permitted)
-- deduct 100 lbs. for GT47-88 with cast head
-- deduct 100 lbs. for GT55-80 with cast inline head and 80 x 130
-- deduct 100 lbs. for GTX-55-85/LF 85
-- deduct 50 lbs. for 8.2
-- add 100 lbs. for inline non-SVA head
-- add 50 lbs. for PTE PM Gen II 88
-- add 150 lbs. for non-inline cylinder head
-- add 250 lbs. for billet head on LF88/GTX-55-88/PTE PM Gen II 85
* Blower Small Block 3050 lbs.
-- base weight set with cast SVA inline/mod motor and F1X or XB105 (add 50 lbs. for M1)
-- deduct 350 lbs. for 8-71 with billet block/cast head
-- deduct 50 lbs. for 8.2 deck
-- deduct 50 lbs. for Billet Xi (add 50 lbs. for M1)
-- deduct 150 lbs. for cast Xi (M1 permitted)
-- deduct 200 lbs. for F1R (M1 permitted)
-- deduct 250 lbs. for F1C-10.5 (M1 permitted)
-- add 50 lbs. for non-inline with billet Xi
-- add 100 lbs. for non-inline/non SVA cast head on F1X or XB105
-- add 150 lbs. for Gen III Mopar billet head (only blower combo permitted with billet head)
-- add 50 for 28 x 10 Pro Bracket Radial
*Small Blocks (NOS & NA) with single 4150 carb/throttle body: deduct 50 lbs.
o *Small Block (NOS) with any plate system: deduct 50 lbs. (does not apply if used in conjunction with a fogger)
o *Small Blocks (NOS & NA) with 23 degree Chevy heads, 20 degree Ford heads, and 18 degree Mopar heads: deduct 100 lbs. Raised Runner -75 lbs.
o *Small Block (NOS only) 18 -10 degree valve angle inline head: deduct 50 lbs.
o *Small Block (NOS only) cast Tunnel Ram/Sheet Metal 2 carbs – 2 throttle bodies: add 50 lbs.
o *Throttle bodies exceeding 4500 series on Big Block NOS combinations: add 50 lbs.
o *Non Intercooled boosted cars on gasoline: deduct 100 lbs.
o * Belt driven centrifugal and roots style superchargers: deduct 100 lbs.
o *Aftermarket rear suspension COPO Chevy and Drag Pack Mopar permitted on the new Camaro and Challengers must be mounted in exact factory location on body/frame. Torque arm on late model GTO and 5th gen Camaro permitted. Corvette with any leaf spring or ladder bar type suspension permitted.
o * Buick/Olds/Pontiac/Mopar B1 Nitrous Combo will be 3000 lbs. and not exceed 588 cubic inches.
o V6/I6/I4 turbocharged – supercharged – nitrous combos will deduct 250 lbs. from base weight on gas and 150 lbs. if on alcohol.
o Factory IRS deduct 100 lbs.
o Deduct 100 lbs. for the 3754R tire
**Cold Nitrous -6 and -4 nitrous line(s) must be of standard braided line construction, (high pressure hydraulic line prohibited as they exceed the internal diameter of industry standard)
Standard spec lines/fittings only.
-4 I.D. .153 to .154
-4 I.D. with -6 Nut .153 to .154
-6 I.D. .275 to .276
Big Block Chevy Cylinder Head:
Conventional Heads as referenced to the original Mark IV design. (BBC symmetrical or raised port design is not defined as conventional for these rules)
- Stock port location/Standard port location – no raised runner
- Floor of port may not be more than .550 from deck
- No port plates or intake manifold adapter plates permitted
- No epoxy or welding permitted except for repair in chambers or between cylinders
- No welding of tops of runners except for adding bolt bosses for rocker stands
- Intake valve angle will measure 24* + or – 1*
- Maximum dimension allowable from deck surface to the top of the intake port will be no more than 3.125”
- Heads with “AS CAST” intake port lower than this dimension will be permitted.
- No welding or epoxy permitted to achieve this dimension.
- Tech official has final say at the time of inspection on any issues that may arise
Suggested castings to include the following:
• CFE/BMF 350 – 405cc Big Block Chevrolet
Chevrolet Factory OEM Iron & Aluminum; OEM Aluminum
• Brodix BB-1, BB-1 OEF1, BB-2, BB-2X, BB-2 Extra, BB-2 Plus, BB-3, BB3X, SR23
(non-raised runner Head Hunter)
• Edelbrock MC - Victor & Victor CNC, Edelbrock Victor Jr. CNC Oval & Rect
• Edelbrock Performer RPM 454-O, 454-O, 454-R
• Edelbrock Victor 24-degree Rectangular Port #77419, #77409
• Edelbrock RPM XT Rectangle PN#51539
• Edelbrock RPM XT Oval PN#51459
• Edelbrock Victor PN#61409
• Edelbrock Victor PN#61419
• Edelbrock Victor PN#77609
Pro – Filer Sniper and SniperX 290 cc 320 cc and 375 cc
• Dart Pro 1 310 cc thru 355 cc, Race Series 265 cc thru 360 cc, Dart 380 Pro2
• Canfield Big Block Chevy 24.5-800, 24.5-900
• GMPP Signature Series BB Heads cast # 12363401, 12363391
• Air Flow Research 265, 290, 305, 315, 325, 335, 345, 357, 385, Oval, Rect & CNC Port
• World Products Merlin II Oval & Rect Port 269, 320, 345, 305, 350 Iron & Alum
• (RHS)Pro Top Line Pro Thunder 320, 360 cc Alum & Iron
Big Block Ford Cylinder Head:
- Factory cast Iron heads (don’t think we’ll see many of them )
- A-429 Cobra Jet (Ford Motorsports)
- Cobra Jet (Blue Thunder, Trick Flow)
- Super Cobra Jet (Ford Motorsports, FRPP/Kaase)
- Blue Thunder “B” head
- Street Heat (Trick Flow)
- Edelbrock RPM
- P-51′s (Kaase)
- “A” designation heads
(All manufacturers, Ford Motorsports, FRPP, Trick Flow, Eliminator, EX514, etc. . .)
Big Block Mopar:
B-1 style cylinder heads only
If one combination appears to have an advantage rules may be changed at the race director’s discretion at ANYTIME in order to keep a level playing field for all competitors.