Last Updated: November 27, 2017
The class designation is LDR. All entrants must
display this designation on both sides of their
car with car number.
This is a 1/8th mile, heads up category running on
a .400 Pro tree with a professional pairing
ladder. This is a single power adder class only!
All NHRA/IHRA and Local Track Safety rules apply
for car and driver, including the use of an oil
retention device and/or engine diaper is
MANDATORY. Any competitor causing an oil down that
does not have an oil retention device will lose 5
points off their to 2018 LDR championship points
The car must retain its original appearance,
profiles and dimensions. No aftermarket one-piece
bodies. OEM door jamb and quarter panels must be
used. No modified front ends to achieve maximum
NHRA/IHRA overhang, must stay within original body
dimensions. Must retain factory body lines with
removable composite components as in hood, front
bumper, front fenders, doors and deck lid. Any
beam tripping devices forward of the bumper are
prohibited. Aftermarket front bumpers (“Ex.
Snowplows or Valances”) cannot have more than 2
inches of overhang over the stock bumper
dimensions, failure to abide by this rule will
result in disqualification. Aftermarket wings and
spoilers are permitted. A hood must be used; scoop
or hood must cover entire induction system.
Exceptions are throttle bodies or carburetors on
naturally aspirated and nitrous oxide assisted
engines along with intake manifolds/throttle
bodies on boosted engines. Those may protrude
through the hood for clearance, if needed. Forward
facing hood scoops/turbocharger/supercharger
inlets are permitted. OEM/Lexan windows are
permitted. Front ends must be within the spirit of
the rules and legality is at the discretion of the
race director. Firewall must be in the stock
location; stock firewall can be modified.
Door cars only, no pro mod or full tube chassis.
Backhalf style cars are permitted. No Wheelie
Bars. Any rear suspension is permitted. Factory
front frame rails are mandatory, they can be
modified and must extend to the center of the
front spindle. Aftermarket front K-Members are
permitted, must bolt in the factory location.
Factory equipped 'bolt-in' subframe cars are
permitted an aftermarket bolt-on front end (Ex.,
Smith Racecraft) for '62-'74 Nova and '67-'81
Camaro/Firebird, must bolt in. Factory wheelbase
for year/make/model must be maintained, (+/- 1
inch). A minimum height of 3 inches from the front
of the vehicle to 12 inches behind front spindle
center line is mandatory. A minimum height of 2
inches for the rest of the vehicle is mandatory
(except for oil pan and headers).
No cubic inch limit for any naturally aspirated or
power adder combination. All engines must have a
diaper, belly pan or oil retention device. Nitrous
oxide is permitted to run any type multi-stage
nitrous system with no restrictions. Nitrous
entries must have bottle securely contained in a
bottle bracket. Maximum bore spacing for all
boosted combinations is 5.000 or less.
Turbocharger combinations are limited to a single
turbocharger at an 118mm maximum, small block and
big block. Billet engine block and billet cylinder
heads combination will carry extra weight
addition, addressed below in the weight
additions/reductions section. Maximum size on all
twin turbocharged combinations are 88mm, small
block and big block. Maximum exhaust wheel
measurements for 88mm twin turbocharged
combinations is 103.5mm, anything over that
dimension will be deemed illegal. Turbochargers
will be verified by measuring the housing bore at
the leading edge of the impeller wheel and must
retain the contour of the compressor housing,
stepped or clipped compressor wheels are
prohibited. Inserts or reducers to achieve inlet
or outlet dimensions are prohibited. Supercharger
combinations are limited to a single centrifugal
supercharger at a F3-139 maximum, small block and
big block. Maximum size on all twin centrifugal
supercharged combinations is base F1X, (F1X-12 is
prohibited). Roots superchargers are restricted to
a 14-71 maximum. Screw superchargers are
prohibited. Dual power adders are strictly
All entries must be self-starting from inside the
vehicle. A master cut-off switch is mandatory on
the rear of the car with an on/off sticker. Any
electronic ignition system is allowed, see below
for weight additions/reductions. Computer/Data
Recorders are permitted.
Mufflers or inserts are required on all cars
except for turbo cars. Exhaust may exit underneath
car or out the front fenders/valance but must not
affect timing or staging beams.
CO2 SYSTEM AND LINE:
The first TWO feet (minimum) of the line coming
from the CO2 bottle must be 1/4" plastic line with
push-locks. No braided steel lines direct from the
CO2 bottle to ensure no nitrous oxide is being
used. Braided steel line may be used after the
first two feet of plastic/push-lock line to
protect the line running through the firewall
and/or around exhaust system.
Any intercooler is permitted on gasoline
combinations only. Must be securely mounted to
chassis or mounts with preferred hardware. Water
box must be contained in a safe environment with a
top to enclose water/ice during the run.
Intercooler combined with a methanol fueled
combination is prohibited.
Any transmission permitted. Any converter
permitted. Lock-Up Transmission/Converter setups
are permitted on naturally aspirated and nitrous
oxide combinations only, prohibited on
turbocharger or supercharger combinations.
Any gasoline, E85 or M1 permitted. M5 is
prohibited. No nitromethane or additives.
Any brand 275/60/15 Drag Radial. Mickey Thompson
295/65/15 Drag Radial (PN: 3558) and Hoosier
295/65/15 DR2 (PN: 17316DR2) will be the legal
tire options for the 'big' tire option. Nitrous
oxide combinations can run any tire at base
weight, no weight penalty on nitrous cars for the
big tire. Any 481X/HEMI or Any Hemispherical
Headed Combination equipped with single
turbocharger, twin turbochargers or centrifugal
supercharger(s) must be on a 275/60/15 drag
radial, no big tire option for that engine/power
adder combination. Must stay on the same tire
throughout the entire event. This officially makes
Limited Drag Radial a DOT tire class in 2018.
All weights are minimum with driver in car.
- Small Block - No Minimum
- Big Block - No Minimum
- Small Block - 2,200 lbs.
- Big Block (4.840 Bore, Any Transmission) - 2,550
- Big Block (5.000 Bore, Any Transmission) - 2,700
- Big Block (5.000+ Bore, No Lockup Transmission)
- 2,850 lbs.
- Big Block (5.000+ Bore, Lockup Transmission) –
- Small Block, Single Turbo - 2,850 lbs.
- Small Block, Twin Turbo - 3,000 lbs.
- Big Block, Single Turbo - 3,100 lbs.
- Big Block, Twin Turbo – 3,225 lbs.
- Small Block, Roots - 2,750 lbs.
- Big Block, Roots – 2,900 lbs.
- Small Block, Single Centrifugal (ProCharger F1
or Equivalent) - 2,800 lbs.
- Small Block, Single Centrifugal (ProCharger F2
or Equivalent) - 2,825 lbs.
- Small Block, Single Centrifugal (ProCharger F3
or Equivalent) - 2,850 lbs.
- Small Block, Twin Centrifugal - 3,000 lbs.
- Big Block, Single Centrifugal (ProCharger F1 or
Equivalent) - 3,050 lbs.
- Big Block, Single Centrifugal (ProCharger F2 or
Equivalent) - 3,100 lbs.
- Big Block, Single Centrifugal (ProCharger F3 or
Equivalent) - 3,150 lbs.
- Big Block, Twin Centrifugal - 3,250 lbs.
- 100 lb. Weight Addition for the 295/65/15 ‘Big’
Tire Option, (MT 3558 or Hoosier 17316DR2).
- 100 lb. Weight Addition for 481X/HEMI or
Hemispherical Headed BBC/BBF.
- 50 lb. Weight Addition for Any ALL Billet
Boosted (Turbo or Supercharger) Combination (Heads
and Block), other than HEMI or 481X.
- 481X, HEMI and Any Hemispherical Headed Engine
must be on 275 Drag Radials if power adder is
single turbocharger, twin turbocharger or any
centrifugal supercharger(s) combination.
- 25 lb. Weight Reduction for Conventional Headed
BBC Combinations on Gasoline.
- 50 lb. Weight Reduction for Centrifugal
Supercharger Combination on Gasoline.
- 50 lb. Weight Reduction for Leaf Spring Rear
*** Rules are subject to review at any time. We
are going to do our best to keep the racing as
tight and competitive for all combinations
throughout the entire 2018 season. ***
Rules from LimitedDragRadial.com
ALSO: EVENT / RACE INFORMATION