NCRS Lingo Defined | NCRS Meaning | NCRS

This page is a work in progress. It is here to help establish a dictionary of NCRS Lingo. New members and old members alike sometimes question what some of the terms used to describe our Corvettes and the restoration process that we go through to make them ready for NCRS Flight Awards. Terms with an * are taken from an official GM Abbreviations/Acronyms Manual.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

A/C: Air conditioner/air conditioning. *
AAP: Auxiliary accelerator pump *
ABC: Assembly broadcast code *
ABL: Assembly breakdown list *
ABS: Adaptive brake system / anti-lock braking system (called ALB by Honda) *
AC: AC Spark Plug Division (of GM, formerly, now AC Rochester) *
AC/R: AC Rochester, Flint MI *
ADC: Advanced Development Center (of C-P-C), Pontiac MI *
AFB: Aluminum 4-bbl carburetor *
AIC: Air intake control *
AIM: Assembly Instruction Manual
AIR: Air Injection Reactor system. * Part of the early smog equipment.
Air Box: Special aircleaner ducted to a hole in the radiator support to provide cool air to the Fuel Injection on 43 race prepared 1957 Corvettes.
ALL: Automatic load leveling ( suspension) *
ALS: All season tire *
alt: Alternator *
AMA: Automobile Manufacturers' Association
APD: Assembly process deviation *
ARC: Automatic ride control (suspension) *
AS: Active suspension system *
ASR: Anti-slip regulator system *
ASSEM: Assembly *
ATDC: After top dead center *
ATS: Air temperature sensor *

B Back

BBC: Big Block Chevrolet engine. Engines that started in 1965 with 396 cubic inches and progressed to 427 cubic inches for 1966 and then to 454 cubic inches from 1970 - 1974.
BC/CC: Base coat/clear coat paint *
BHP: Brake horsepower *
Big Block: Engines that started in 1965 with 396 cubic inches and progressed to 427 cubic inches for 1966 and then to 454 cubic inches from 1970 - 1974.
Big Brake: Big Brake option available on 1957 through 1962.
Big Tank / Tanker / No Carpet Club: Optional larger gas tank, available 1959 through 1967.
Bolt on Wheels: Aluminum wheels on 1967 Corvette that appeared very much like the 1963-66 Knock-off wheels, except that they bolted on just like standard wheels.
BOM: Bill of materials, used at prototype build sites as part number list for each vehicle *
Broach Marks: The marks on the deck of the block including the stamp pad, created by the factory machining operation. Broach tool; leaves lines as the cutter moves across the deck in a straight line from front to back. The ridges or grain of the marks will vary quite a bit from engine to engine as the tooling wears or other factors enter into the process. Re-stamped blocks are first decked to erase the original numbers and; most automotive machine shops cut and leave broach marks across; the block side to side, which are readily detected when inspecting a stamp pad. However, some very cleaver and expensive shops cut the blocks like the factory so they can re-stamp and be nearly undetected.
BPEGR: Back pressure exhaust gas recirculation *
BSW: Black sidewall tire *
BTC: Body Technology Center *
BTDC: Before top dead center *
Build sheet, Tank Sticker: It lists all the options the car had originally. Starting in with '67s, it is glued to the top of the gas tank. Later years also may find them stashed various places inside the car. A great piece of authentication, since Chevy has no records of how each car was equipped. The National Corvette Museum has recently been given access to copies of all of the build sheets from the Bowling Green Plant. This applies to 1981 and later cars that were manufactured at Bowling Green. The Museum is now offering a service of reproducing a copy of the build sheet and the Window Sticker. See the NCM web site for further information. Like everything else, can be faked.
BWO: Build work order *

C Back

C1: 1953 -1962 Corvettes. The solid axle or straight axle cars.
C2: 1963 - 1967 Corvettes. Mid-years and Sting Ray years.
C3: 1968 - 1982 Corvettes. Includes 1968 Shark, and 1969 - 1976 Stingray years.
C4: 1983 - 1996 *note: There were no 1983 production cars due to plant change over from St. Louis to Bowling Green.
C5: 1997 - 2004 Corvettes.
C6: 2005 - 2013 Corvettes.
C7: 2014 - 2019 Corvettes.
C8: 2020 - and later Corvettes.
CAFE: Corporate average fuel economy *
CAMSHF or CAM: Camshaft *
Casting Number: Part number cast into a part as it is produced. Many castings also have a date code cast into the part as well. Parts such as blocks, manifolds, heads, transmission cases, differential cases and many more have casting numbers that identify them as particular to certain applications. On most Chevrolet blocks the casting number is located on the bellhousing flange behind the driver's side head. This can usually be seen even with ignition shielding in place.
CB: Citizens band (radio) *
CDCIF: Configuration, Date, Completeness, Installation, Finish, each area judged is 20% of total originality points
CDI: Capacitor-discharge ignition system *
CEL: Check engine light (display) *
CFI: Cross fire injection *
CID: Cubic inch displacement (of engine) *

COM: Chassis Overhaul Manual

Convertible: Cars with a fold down canvas like top, and roll up windows.
COPO: (Chevrolet) Central Office Production Options (formerly), now SEO * Combinations of options that were generally not available to the public. The order was generated through the Chevrolet Central Office.
Coupe CPE *: A closed car with two doors.
CPO: Chevrolet part number only *
Crossfire Injection: Standard on 1982 & 1984 model's only. First fuel injection since 1965 two injectors in a throttle body setup.
CSM
Chassis Service Manual
CVJ: Constant velocity joint *

D Back

Date Code: Almost every mechanical part made for a Corvette has a date code either cast or stamped into it. These are used by the manufacturer to track quality control. They are now used to determine if the part is probably correct for the Corvette it is installed on. An engine with a date code of C 10 4 (March 10, 1964) could not be correct for a '63 Corvette as the engine was made after the car was made. Parts too early are usually not correct either, as they would have been installed on an earlier vehicle, such as a D 19 5 (April. 19, 1965) in a '67 Corvette. The date code on an engine block is typically on the bellhousing flange behind the distributor. On early big blocks, it was on the passenger side near the pan rail, but later (1970) moved up to the same location as the Small Blocks.

DIST: Distributor (an engine part) * Distributes spark from coil to spark plugs. Controls spark timing.
DLI: Distributorless ignition system *
Documentation, History: Depends on who is listening to the pitch. Many cars have no documentation or history. It is a good thing to have. You can check up on when modifications were done, where stuff like missing ignition shielding went, etc. If there is something atypical about the car, like a hand-stamped block, you can sometimes get affidavits from former owners that this is the original block and was never removed from the car.
DWO: Design work order
DYNO: Dynamometer * Device for measuring mechanical force, or power.

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EAM: Engine assembly manual *
EC: Engineering change *
ECS: Electronic Controlled Spark
EEC: Evaporative Emission Controls
EFI: Electronic Fuel Injection
EGR: Exhaust gas recirculation *
EIN: Engine identification number *

F

FI - Fuelie: Fuel Injection. Early cars 1957 - 1965 used Fuel Injection that was unlike our modern electronic Fuel Injection cars of today. They often were very difficult for mechanics to adjust or maintain. They were often taken off of cars and replaced with carburetors. That history leads to today's restored Fuel Injection cars being a little rare.

G

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GMSPO: General Motors Service Parts Operations *

H

H/prf - HI-PERF - HP: High performance *
HEI: High energy ignition system *
hp: Horsepower * One hp equivalent of 550 ft. lbs. per second

I

J

Judge: NCRS Judges are volunteer members who offer their time and knowledge to Judge Members Cars under the guidance of the NCRS Technical Information Manual & Judging Guide. Master Judge (see Master Judge).

K

K-H: Kelsey-Hayes Co., Romulus, MI
King of the Hill: See ZR-1
Knock Off / KO / Knock Off Aluminum Wheel Option: Optional wheel available during 1963? or 1964 through 1966 Model years.

L Back

L - series engines were designated by their RPO Numbers. See RPO.

1963 -

L75: 300 hp w/AFB - L76: 340 hp w/AFB and Hi-Lift Cam - L84: 360 hp w/FI and Hi-Lift Cam

1964

L75: 300 hp w/AFB - L76: 365 hp w/Holley and Hi-Lift Cam - L84: 375 hp w/FI and Hi-Lift Cam

1965

L75: 300 hp / 327 - L76: 365 hp / 327 and Hi-Lift Cam - L78: 425 hp / 396

L79: 350 hp / 327 with AFB and hyd/Hi-Lift Cam - L84: 375 hp w/FI and Hi-Lift Cam

1966

L36: 390 hp / 427 - L72: 425 hp / 427 - L79: 350 hp / 327

1967

L36: 390 hp / 427 - L68: 400 hp / 427 - L71: 435 hp / 427 - L79: 350 hp / 327

L88: 430 hp / 427 - L89: 435 hp w/ Aluminum Heads

1968

L36: 390 hp / 427 - L68: 400 hp / 427 - L71: 435 hp / 427 - L79: 350 hp / 327

L88: 430 hp / 427 - L89: 435 hp w/ Aluminum Heads

1969

L36: 390 hp / 427 - L46: 350 hp / 350 - L68: 400 hp / 427 - L71: 435 hp / 427

L88: 430 hp / 427 - L89: 435 hp w/ Aluminum Heads

1970

L46: 350 hp / 350 - LS5: 390 hp / 454 - LT1: 370 hp / 350

1971

LS5: 390 hp / 454 - LS6: 425 hp / 454 - LT1: 330 hp / 350

1972

LS5: 270 hp / 454 - LT1: 255 hp / 350

1973

LS4: 275 hp / 454 - L82: 250 hp / 350

1974

LS4: 270 hp / 454 - L82: 250 hp / 350

1975

L48: 165 hp /350 - L82: 205 hp / 350

1976

L48: 180 hp / 350 - L82: 210 hp / 350

1977

L48: 185 hp / 350 - L82: 210 hp / 350

1978

L48: 185 hp / 350 - L82: 220 hp / 350

1979

L48: 195 hp / 350 - L82: 225 hp / 350

1980

L48: 190 hp / 350 LG4:180 hp / 305 (California Legal) - L82: 230 hp / 350

1981

L81: 190 hp / 350 Legal for 50 States. No optional engines offered.

1982

L83: 200 hp / 350 Legal for 50 States. No optional engines offered.

Long Block: Replacement engine assembly includes block, crank, cam, pistons, rods, heads and valve train components all assembled and ready to install. Timing gears and chain are also included. The oil pump is commonly installed. This is the basic engine including all of the parts for that base engine. Things like covers, waterpumps, flywheels, and other parts that may vary depending on the application are not included. This engine may be serviceable in a Corvette or a 9 passenger van. Either with an automatic transmission or four speed. Fuel delivery may be carburetor, or fuel injection. This is why certain parts may be included on one version and deleted on another. GM refers to this as a "Targetmaster" engine.

M Back

Master Judge: NCRS Master Judges are volunteer memberswho have been recognized by the organization and membership for accumulating a minimum of 100 points in our judging recognition program by Judging at events, attending Judging Schools at Chapter Meets, Regional Meets and National Meets. Many have also attended National or Regional Judging Seminars that last for one or two days of intensive instruction and hands on participation.

NCRS 200 Club:

An individual who has been recognized by the organization and membership for accumulating a minimum of 200 points in our judging recognition program.

NCRS 300 Club:

An individual who has been recognized by the organization and membership for accumulating a minimum of 300 points in our judging recognition program.

NCRS 400 Club:

An individual who has been recognized by the organization and membership for accumulating a minimum of 400 points in our judging recognition program.

NCRS Red Hat Master Judge:

An individual who has been recognized by the organization and membership for accumulating a minimum of 100 points in our judging recognition program, and participating as an owner in the judging program achieving one of our highest awards offered, either the NCRS Duntov Mark of Excellence, the NCRS McLellan Mark of Excellence, the NCRS Hill Mark of Excellence, or the NCRS-Chevrolet Bowtie Preservation Award.

NCRS Master Tabulator:

An individual who has been recognized by the organization and membership for accumulating a minimum of 100 points in our tabulation recognition program.

Midyear: 1963 - 1967 Corvettes. Mid-years and Sting Ray years.
Mouse Motor: Chevrolet small block 265,283,302,327,350 are often referred to by the term "Mouse Motor".
MSRP: Manufacturers suggested retail price including dealer preparation *
MPL: Master parts list (computer code) *
MVMA: Motor Vehicle Manufacturers' Association (successor to AMA)

N

NCM: National Corvette Museum. Bowling Green, KY. Just across the road from the Bowling Green Corvette Plant. NCM web site
NM: *NM* NCRS Technical Discussion Board and NCRS Discussion Board. Identifies a message with no content, or no message.
NOM: Not Original Motor. This may or may not matter to you, but it probably will to someone else if you have to sell the car later. Pay less for NOM.
NORS: NORS refers to New Old Replacement Stock. These are parts that have been laying around in their original boxes since who knows when. They are usually preferred over reproduction parts, but they are not always correct for your car. There were many parts for our Corvettes that were used on the assembly line that were never sold as replacement parts. For any number of reasons the replacement parts could be configured differently than the parts that the car was delivered with. That is one of the reasons that NCRS is so serious about Bowtie cars. These are examples of cars that remain unrestored, unmolested original cars. They may not look like much to the casual observer, but to many NCRS members they are a living laboratory where we can see how the factory assembled these cars and what parts were used on the days that our example car was assembled.
NOS: NOS refers to New Old Stock. These are parts that have been laying around in their original boxes since who knows when. They differ from NORS in that the part is identical to the part used during assembly. The problem here is knowing NOS from NORS. Experience and consulting with Team Leaders, Master Judges, and other trusted sources is the only way to know.

O Back

OEM: Original Equipment Manufacture. Many times these are not manufactured by GM but subcontracted to one or more vendors. The parts from different vendors may vary slightly. These parts often were and are mixed during the production runs.

P

Partial Engine: See Short Block.
PBM: Prototype build manual *
PCV: Positive crankcase ventilation *
Performance Parts Engine Assembly "GM": A high performance SERVICE engine assembly usually configured differently than any available PRODUCTION engines. It is composed of PRODUCTION and GMPP components
PG: Powerglide Transmission
PID: Part identification (in MPL) *
P/N PTN: Part number
Positrac / Positraction / Posi: Limited slip differential.
Production Engine Assembly: A full-dressed PRODUCTION engine, just as delivered to the vehicle assembly plants, which is sold through SERVICE. These are exactly the same as the engine installed in passenger cars or trucks. PRODUCTION engine assemblies are usually only available during the current model year or until GMSPO inventory of the PRODUCTION engines is exhausted.
Protect-o-plate: This a metal warranty card which has the original purchaser's name on it. It also has some information on the original configuration of the car, not as extensive as the build sheet. It was first included in 1965.

Q

R

Rat Motor: Chevrolet big blocks of any year 348ci, 366ci, 396ci, 402ci, 409ci, 427ci, 454ci were referred to as "Rat Motors".
Roadster: 1953 -1955 Corvettes were roadsters, they had side curtains, no roll up windows. NCRS does consider Convertible the same as Roadster.
RPO / Regular Production Option *: Optional equipment from engines to vanity mirrors that were generally available to the public.

S Back

SBC: Small Block Chevrolet engine. Chevrolet engines derived from the 265 cubic inch, block design first introduced in 1955. SBC's include 283's, 302's, 305's, 307's 327's, 350's, and 400's.
Service Engine: This is an engine assembly which is composed of all PRODUCTION pieces and is configured the same as a PRODUCTION configuration. It usually lacks some of the peripheral components which must be transferred from the replaced engine or otherwise acquired. When completed, it will have the same configuration as the replaced engine.
Shark: 1968 Corvettes were designated Shark.
Side Pipe / Side Exhaust: Optional equipment available on 1965 through 1967 and 1969.

Short Block: Replacement engine that usually includes only the block, crank, connecting rods, pistons, camshaft, timing gears and chain. It is all assembled and ready for heads and valve train components, intake manifold, carburetor or fuel injection, exhaust manifolds, and other items too numerous to mention. This referred to as a "Partial Engine" by GM
SHP / Special High Performance: A Higher performance carburetor engine, either small block or big block, generally with a mechanical lifter cam, however, some had special hydraulic lifter cams.
Small Block: Chevrolet engines derived from the 265 cubic inch, block design first introduced in 1955. SBC's include 283's, 302's, 305's, 307's 327's, 350's, and 400's.

Sting Ray: 1963 - 1967 Corvettes were designated Sting Ray. Note there seems to be some question of the 1968 model was it a Sting Ray, or a Stingray, or neither?
Stingray: 1969 - 1976 Corvettes were designated Stingray.
Straight Axle / Solid Axle: 1953 -1962 Corvettes. These are the Corvettes that predate the 4 wheel independent suspension of 1963 and later cars.
SWC - S/W/C * Split Window Coupe: 1963, only Corvette Coupe with the two piece rear window. One year only feature due to poor rear visibility.

T Back

T-3: Guide Lamp T-3 headlamps used from 1956 to 1972 in different configurations.
T-top: Removable top panels. Two panels one over the drive seat and the other over the passenger seat.
Tank Sticker, Build Sheet: It lists all the options the car had originally. Starting in with '67s, it is glued to the top of the gas tank. Later years also may find them stashed various places inside the car. A great piece of authentication, since Chevy has no records of how each car was equipped. The National Corvette Museum has recently been given access to copies of all of the build sheets from the Bowling Green Plant. This applies to 1981 and later cars that were manufactured at Bowling Green. The Museum is now offering a service of reproducing a copy of the build sheet and the Window Sticker. See the NCM web site for further information. Like everything else, can be faked.
Targa Top: Removable single top panel. Opens car roof from side to side.
Target Engine: See Long Block.
TBI: Throttle body injection *
TCS: Transmission Controlled Spark. Common in late 60's early 70's.
THM: Turbo Hydra Matic Transmission
TL: *TL* NCRS Technical Discussion Board and NCRS Discussion Board. Used to denote posts by NCRS Team Leaders or other NCRS Officials. It is used to identify posts as being genuine.
TI / Transistor Ignition
Tri Power / 3 deuces / 3 X 2 / Three two Barrel Carburetors
TRW: Thompson-Ramo-Wooldridge ( a GM supplier ) *
TCS: Transmission Controlled Spark
TWO: Test work order

U

V

Z06: Vacuum Advance Control

Z06: Vehicle Identification Number *
Z06 Shield: Ignition shielding on lower sides of engine block.

W

X

Y

Z Back

Z06: The "ZO6" was the hottest '63 Corvette variation. Equipped with heavy-duty suspension and heavy duty brakes, it was only available as a 327 cubic inch 360 horsepower, fuel-injected 4 speed transmission Coupe. Early production provided a special 36 gallon fuel tank, later versions could be ordered with a standard fuel tank. 199 ZO6's were built, and less than 90 are believed to have been the "big tank" version.
ZR1: 1970-72 Special Purpose Package: (Not recommended for normal traffic situations) Includes LT1, 370-hp 350 cu-in. engine, special 4-speed close-ratio transmission, HD power brakes, full transistor ignition system, aluminum radiator, special springs with matching shock absorbers, special front and rear stabilizer bars. 1972 included 255-hp engine available for registration in California.
ZR-1: 1990-95 LT5 engine, an aluminum-block V-8 with the same bore as the standard (L98) 350ci displacement unit, but with 375 horsepower. To accomplish this power boost, the new block featured four overhead camshafts and 32 valves. The LT5s were built by Mercury Marine in Oklahoma and assembled into the ZR-1 vehicle at Bowling Green. Available only in coupe configuration, the ZR-1 was distinguishable from other Corvette coupes by its wider tail section, its now convex rear fascia and four "square" taillights. 6,939 ZR-1s were turned out.
Z06: 1971-72 Special Purpose Package: (Not recommended for normal traffic situations) Includes LS6, 425-hp 454 cu-in. engine, special 4-speed close-ratio transmission, HD power brakes, full transistor ignition system, aluminum radiator, special springs with matching shock absorbers, special front and rear stabilizer bars.

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