It happens all the time... people want to know how to break down the Regular Production Order (RPO) codes on their new C4!

Let's create our own list, and not send members to other forums!

To find your RPO code, check under the center console, or the left rear storage bin.

Confirm that the VIN number matches your car! It's quite common for a new center console to be installed without consideration for the RPO sticker!

If you want a build sheet, contact the Nation Corvette Museum at http://www.corvettemuseum.com/.

Some of these RPO's, I am sure came from The Corvette Black Book (various years) by Michael Antonick.

Some of these RPOs are independant of themselves. For example, one RPO indicates that the manual transmission was selected, where another indicates WHICH manual, even though only one was available... which must be some kind of leftover from when there were 3 different manual transmissions (back in the 60s, there was the 3 speed and two different 4 speeds).

First off, though, what is an RPO? It is the Regular Production Order code. These codes were assigned by GM to keep track of options and activities during the manufacturing of a car. These numbers are not reflective of anything other than what code was available at the time it was assigned. However, some codes have taken on meanings unto themselves, such as the Z28 Camaro, or the ZR1 Corvette. The "Z28" and "ZR1" are both the RPO codes assigned to that option package.

Same thing goes for the old W30 Cutlasses and WS6 Firebirds of the day. At times, GM will establish an RPO that stays within a specific option group. For example, the LT1 option has been reused, as has LS6. They both harken back to a bygone era and sound cool. In short, they are instantly recognised as being performance options.

The list:

1YY07 - Base Coupe
1YY67 - Base Convertible

1AZ - Modification stock order or order sold
1SB - Marketed option package 2
24S - "Removable Roof Panel, blue tint"
64S - "Removable Roof Panel, bronze tint"
AC1 - Power Passenger Seat
AC3 - Power Driver Seat
AJ3 - S.I.R. system (driver side only) 90-93
AK5 - Front seat S.I.R. system (driver & pass.) 94-96
AQ9 - Leather Sport Seats
AR9 - Base Leather Seats
AU3 - Power Door Lock System
B2K - Callaway Twin Turbo Engine (on Bowling Green Twin Turbos)
B4P - Fan, Aux Cooling, Electric
BGR - Bowling Green assembly plant
C05 - convertible folding top
C2L - Dual Removable Roof Panels
C49 - Electronic Rear Window Defogger
C60 - Manual Air Conditioning Controls
C68 - Electronic Climate Control
CC2 - Auxiliary Hardtop (convertible only)
CC3 - Removable Plastic Roof Panel
CF7 - Removable Roof Panel (Solid Body Color)
D3X - Speedometer Driven Gear (25513049)
D4L - Speedometer Driven Gear (25513050)
D7B - Speedometer Driven Gear (25513043)
D7C - Speedometer Driven Gear (25513045)
D8E - Vehicle Speed Sensor (10456021)
D8F - Vehicle Speed Sensor (10456022)
D8H - Vehicle Speed Sensor (10456039)
DC7 - Electronic LH & RH Outside Mirrors
DC8 - Electronic LH & RH Outside Mirrors
DL5 - roadside service information decal
DL8 - LH/RH Heated Sport Mirrors
E5C - Delete speedometer adaptor
E9Z - Delete speedometer key
EXP - Export
F45 - Adjustable Suspension
FE1 - Base suspension
FE3 - sport suspension (96 Z51)
FE7 - Heavy Duty Suspension
FE9 - federal emissions
FX3 - Adjustable Suspension
G44 - 3.07 Rear Axle Ratio
G87 - ring gear 8.50 inch
G92 - Performance Axle Ratio
GHO - 3.54 axle ratio
GM1 - 2.59 Rear Axle Ratio
GM3 - 3.45 Rear Axle Ratio (8.5 in. Ring Gear)
GT7 - 3.33 rear axle ratio
GU2 - 2.73 Rear Axle Ratio
IP3 - Interior trim design P3
J55 - Heavy Duty Brakes
JL9 - Antilock Front and Rear Disc Brakes
K05 - Engine Block Heater (Canada Export only)
KC4 - oil cooler
KG9 - 140 amp generator
KW2 - 124-Amp Generator
L83 - 1984, standard engine, Crossfire, 350ci, 205 hp.
L98 - 1985-1991, standard engine, 350ci, 230~250hp.
LT1 - 1992-1996, standard engine, 350ci, 300 hp.
LT4 - 1996, optional engine, available only with manual transmission, 330hp
LT5 - 1990-1995, optional engine, part of ZR1 package, 375hp, in 1993, upped to 405hp.
MD8 - 4-Spd. 4L60 Automatic Transmission
ML9 - manual 6-speed, ZF-transmission
MN6 - 6-speed manual transmission
MX0 - automatic transmission
NA5 - Federal Emission systems
NK4 - Sport Leather Steering Wheel
NN5 - California Emission Requirements
QA1 - Wheel, 17 x 9.5, Aluminum
QA2 - Wheels, 17 x 9.5 (Front) 17 x 11 (Rear), Aluminum
QB6 - aluminum wheels 17 x 8.5" front, 17 x 9.5" rear
R9Z - Control sales item 100
T61 - Daytime Running Lights
U19 - Miles & Kilometers Dash Cluster
U1F - Delco Bose Stereo System w/ CD
U52 - Electronic Instrument Cluster
U75 - Power Antenna
UJ6 - Low Tire Pressure Warning System
UM6 - "Bose Stereo w/ CD & Cassette, Seek/Scan, Clock, ETR Radio"
UU8 - Delco Bose Stereo System
UXO - Dual Floor Sill & Extended Range Speaker System
VM3 - information label, bumper impact standards
V56 - Luggage Rack (convertible only)
V73 - Vehicle statement, US or Canada
XAA - front tire P255/45 ZR17
XAU - Front Tire, P275/40ZR17
YAA - rear tire P285/40 ZR17
YAU - Rear Tire, P275/40ZR17
YBE - Rear Tire, P315/35ZR17
Z07 - Handling suspension
Z51 - Handling suspension
Z52 - Handling suspension
Z5G - Identification, Callaway Orders (not listed on SPI label all years)
ZR1 - Special Performance Pkg.

Colour codes:

Exterior

10U - Arctic White exterior

Interior

70I - Torch Red interior
703 - Torch Red leather

Rear Differentials

This topic gets picked on quite frequently. Time to clarify it. There are two differentials, the D44 and the D36 (not RPO codes), both made by Dana. The D36 is standard on the automatic and the D44 is standard on the manual, expection being 1984, when the D36 was the only one available.

These are the codes related to the rear gearing, with the differential that they use:

G44 - 3.07 Rear Axle Ratio - D36, optional; D44, standard, pre-1992.
G92 - Performance Axle Ratio - Shows performance axle selected.
GHO - 3.54 axle ratio - D44 only.
GM1 - 2.59 Rear Axle Ratio - D36 only.
GM3 - 3.45 Rear Axle Ratio - D44 only.
GU2 - 2.73 Rear Axle Ratio - D36 only.

What this means is this, G92 is not dependant on a specific ratio or differential housing. It's just an indicator, a rather redundant one when you think about it.

There is a D44 offered with a 3.33 or 3.31, don't have that RPO yet.

======================================== =
Thanks for providing RPO's!!!

- *89x2*
- 90EXPVette
- jd v3tt3
- ODA CDR
- Strike3
- vms4evr
- Z07 freak

======================================== =

Ok, let's start filling in these blanks! As you all add them, I will post them in this document, then yours can be deleted, to keep the thread smaller.

Same goes for errors and such! This thread does not need to get to 1000 posts.

 

B2K - Callaway Twin Turbo Engine option (on Bowling Green Twin Turbos)
Z5G - Identification, Callaway Orders (not listed on SPI label all years)

 

I have a 90 6 spd coupe, my Label has GT7 & G87; none of the codes listed above. Anyone know what these are? i was under the impression the manual trans cars had 3.07's...

 

3.33 on manuals...add EXP for export model

 

If Rottie is still a member here, he compiled all RPO codes for 1996 Corvettes. I have a hard copy of it. It has the code, description, quantity, cost and comments. If there is enough enthusiasm, I will digitally recreate it. By the way its 18 pages long. Email me at rcelli@hotmail.com, Regards, Ron

 

I have emailed Mike Antonick on this one. I am curious if the RPO has been decoded correctly, or is the result of a typo somewhere down the line.

(see? not starting an arguement!)

 

Like I said on the other thread: 1) it's on my window sticker as GHO--3.54 axle ratio, 2) It's on my build sheet as GHO--3.54 axle ratio, and 3) it's stamped on my differential. No, I'm not taking it out to count the teeth. I'll just have to live with the "Fabled Legend" Vette.

 

I am adding the unimportant ones, just so they are answered!

Please delete older threads! Wanna keep this neat!

My thinking is simple, I don't want people to think they need to read through pages and pages of posts.... it's all there!

Now, with that in mind, did I get everyone properly credited so far?

 

Geez... we could write volumes!

My goal is to list the RPOs... limitations in presentation make more info too complex to display.

If I had the ability to add an attachement, perhaps an Excel spreadsheet would be neat, or an Access Database?

 

Here's my suggestions to label the following;

FE1 - base "soft" suspension
FE3 - "sport" suspension, w/`96 Z-51 only
FE7 - "heavy duty" suspension, w/ `84-90 Z-51, `91-95 Z-07
FX3 - adjustible shock absorbers "selective ride control" `89-95
F45 - adjustible shock absorbers "real time dampining" `96
Z07 - heavy duty adjustible suspension package, `91-95 (cpe. only)
Z51 - heavy duty suspension package `84-90 (cpe. only)
Z51 - sport suspension package `96 (cpe. only)
Z52 - sport handling package `87-88
ZR1 - special performance package `90-95 (cpe. only)

 

Code "GT7" was used from 1989 to 1991 (last year my book covers). It designates a 3.33:1 rear axle ratio. The "G87" code was used from 1976 to 1991 (last year my book covers) as the designation for: "Gear, Ring, 8.50 Inch.". For those that aren't aware, the 8.50" ring gear is used in the Dana 44 rear axle. So for all practical purposes, in a C4, "G87" = Dana 44. There IS a GM 10 bolt axle with an 8.5" ring gear, which is why the designation predates the C4.

RACE ON!!!

 

Oh... this is getting interesting!!!

An email exchange between Mike Antonick and me:

 

GH0 3.54 was used on early `89 ZF6-speeds, then replaced with GT7 3.33 for `89 &`90 L-98 ZF6-speeds.
I have seen a build sheet for an `89 ZR-1 (prototype) with the GH0 3.54 rear axle.
Strick is the only one I know of to claim to have a GH0 3.54 ZF6-speed with an LT1. He says the window sticker, build sheet and stamp on the differential verify this, then I'll take his word.
Is it an early production number? Maybe the designers decided this "lower" gear would work better with the LT1s specs? Are there any other `92 manuals with this gear? Maybe it fall under the same rareity of the `67 small blocks that received big block hoods from the factory for about three weeks because of supply shortages?

 

you may be right.... perhaps they Dana simply sent 3.54's as a mistake... then corrected it with 3.45's.

but I would think a gear change would require EPA recertification.

 

Okay guys, here is my vin# 1G1YY33P3N5105267. So I would guess that with it's plant sequential number of 105267, that it was an earlier built Vette in the 92 run. Also for Mike Antonick, use it for research. Do you want a picture of my differential? I'll have the exhaust off this weekend and a clear shot at the engraving.

 

I am no longer denying the existance of the gear... what we are now trying to figure out is the scope.

When and why it was offered.

if it was an option, is there a price associated with it?

I am going to check mine and see what it really is!!!

 

I think it was probably put on because of availability of parts. Maybe they ran out of 3.45s that day and needed something quick.

 

that is possible... very likely, knowing GM, but wouldn't that require another EPA test?

 

Good question. My window sticker says 17mpg and 25 mpg. Is this different to other 92's?

 

I checked the Corvette Article archive.... according to the 1992 road test from Car & Driver, EPA was as you stated... and their car was a 3.45 car.