Second Generation Camaro Chassis Information

Camaro Rear Axle Identification and Decoding

This stamp can be difficult to locate on an 30+ year old axle due to layers of paint, undercoating, grease, and dirt. It may be necessary to partially strip the forward face of the passenger side axle over the middle third of the length in order to locate and discern the characters. A razor blade and/or putty knife, fine wire brush, and cleaning solution may be needed tools in this search.

1970 Axle code example: COZ 01 01 G E
(COZ = Ratio, 01 = Month, 01 = Day of month, G = Plant, E = positraction source)

1971+ Rear Axle Code example: CB G 112 1 E
(CB = Ratio, G = Plant, 112 = 112th day of year, 1 = shift, E = Positraction Source)

Positraction Source/Code:

- = No positraction		G = Chevrolet G&A Positraction Carrier
D = Dana Positraction Differential		O = Oldsmobile Positraction Carrier
E = Eaton Positraction Differential		W = Warren/Warner Motive

Positraction Casting Numbers
Due to the possible confusion with gear ratio descriptions... a HIGHER number is a LOWER gear.
In the below examples, 2.73:1 & down = 2.41, 2.56, etc... which is actually a HIGHER gear ratio.

Rear Housing Casting Date Example: D141 - (D = Month, 14 = Day, 1 = Last digit of year (1971)). Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec

Axle Ratio   Tooth Combination 2.56:1   41,16 2.73:1   41,15 3.07:1   43,14 3.08:1   40,13 3.08:1   37,12 3.31:1   43,13 3.36:1   37,11 3.42:1   41,12 3.55:1   39,11 3.73:1   41,11 4.10:1   41,10 4.11:1   37,9

Brake System - Dual circuit hydraulic system with warning light and self adjusting features. Metering and proportioning valves provide balance between front and rear wheels.

Yearly Changes?
1970 - 1972, 1973-1974 Similarities, differences.

Here's a trick:
You want to retain your Z28's origonal steering feel, but your steering box is all messed up. What happens if/when you go to speedy's-autoparts and get another steering unit? You ask for a Z28 unit. Will it be a Z28 unit, or will it be for a normal camaro? Are you spending the extra bux to get the "z28" unit only to be sold a crap, slushy, stock unit? (this idiot will never be able to figure it out anyway).
Ask for the part number for a camaro steering box. It'll be something like ABC123.
Now ask for the Z28 unit. If the part number is ABC123, you know what's up. If the part number comes back as XYZ123, chances are, you're getting the good stuff.
THE ONLY WAY TO GUARANTEE YOU'RE GETTING WHAT YOU WANT is to DOUBLE CHECK THIS INFO and order it over the counter at the Chevrolet dealer.

Steering Gears & Valving
My Z28 information will identify the Z28 steering rate vs. stock. Now, how do you identify, at a glance, what box is what? The trick is in the valving of the gear unit.
Note: 800 gear cover retained by bolts. 605 gear cover retained by retaining ring.

Year		Part Number		Description
1971-72		3996780		(Camaro w/PS, Gear unit, power basic, variable ratio)
1971-72		7808369		Camaro - valve
1972		7815770		(Camaro - exc p/s, spec. h/per. 350)
1973		7818145		(Camaro - exc P.S. 8 cyl. Pass, exc police)
1973-75		7818138		(Camaro - w/PS, exc. R.T.S, sport susp). (Radial Tuned Suspension?)
1973-75		358938		(Camaro - w/PS) Gear Unit
1973-75		7808369		Camaro (exc sp. hp 350) - valve
1975		7814930		Camaro (exc RTS) - valve
1976		358938		Gear kit (use with adapter kit 358942 or 358990)
1976		7808369		Valve (w/hd suspension)
1977		7833307		(exc Z28, HD) (F41) Gear, hyd strg (800 gear)
1977		7826116		Valve (exc HD suspension) Note 3
1977		7826113		Valve (HD susp & PS)
1978		7826116		Valve (exc HD susp, 605 gear)
1979		7826116		Valve (exc HD susp, Z28)
1979-81		7832058		Valve (exc HD susp, Z28)
1977-79		7833307		(exc z28) Gear, hyd strg (800 gear)
1979		7826113		Valve w/Z28.
1980-81		7848139		(V6 exc HD susp) Gear
1980-81		7848140		(V6 w/hd susp)
1980-81		7848139		(V8 exc HD susp, Z28)
1980-81		7848140		(V8 w/hd susp, exc Z28)
1980-81		7833147		(w/z28) Gear, hyd strg (800 gear)
1980-81		7834284		Valve (w/800 gear)

Source: General Motors Chassis and Parts catalog.
Chassis Group 6 (Front suspension steering), section .508, steering gear
section .550 Valve Assy - adapter assy., steering gear hydraulic.
AMA data

Spring Rates, part numbers & Info
Figuring out what springs were supposed to be used takes a few steps, and due to the huge amount of spring offerings used each year depending on options, I'll put the spring information in chart form as it's done in Group 7 of the parts manual.
Again, I'm mainly concerned about the Z28 and how to recreate that sort of handling. Where appropriate this information will be linked into or back to specific year information.
Also, use this material as a REFERENCE IF YOU WISH TO MODIFY YOUR CAMARO'S HANDLING. Rather than throw money away chasing something you didn't define, understand what the stock spring was supposed to be, and what the Z28 spring was, and determine what you want to do to the car, and order the correct springs for your application. As of right now, I see a lot of part numbers, but no spring rates. When you have springs made for you, you request a specific rate of stiffness. Again, my Z28 info will identify the specific spring rate.

Jump to spring reference or suspension research
Group 7, Chevy Spring Charts - Figuring out what was stock.
High performance chassis handling - Selecting springs & suspension tuning info

Sway bars/Anti-Roll bars
Again, the Z28 info identifies specific bar diameter. The above performance chassis tuning and auto formulas will help you identify the correct diameter bar(s) for what you want the car to do.

Year		Part Number		Description
1970		3984557
1971-72		3984557		(all) 1.00"
1973-74		3984557		(Camaro w/spec perf susp) 1.00"
1975		356530		(Camaro w/spec perf susp) 1.00"
1973-75		481471		(Camaro exc sp. H/per. 350) rear 0.562" diam
1970-75		3983085		(Camaro w/sp. perf susp, Z28) rear 0.688" diam
1976-77		356530		(Camaro Front 25.400mm)
1976-81		481471		(Camaro w/HD susp, exc Z28) rear 0.562"
1977-81		356534		(Camaro w/Z28) front 31.75mm
1978-81		356530		(Camaro exc Z28 front 25.400mm)
1978-81		3983084		(Camaro w/HD susp, Z28) Rear 0.625")

Camaro Spring Charts

Steps to using the charts - beginning with 1972
1. Select the model desired with the base spring weight on chart "A".
2. Then select options accordingly shown on chart "B" and add that weight to the base spring rate
3. When accumulated weight has been determined refer to chart "C" and select correct spring.

This information is useful to see the difference between std/hd, Small block, big blocks, etc... and how the different cars are balanced. It may also help answer the question "I'm putting a big block in my 1975 Camaro, do I have to change the front springs?" As with anything else on my site, EMAIL ME if you need me to get off my ass and finish a certain section. I get sidetracked easily. (family/real job/9 cars...)

Chart "A", Front/Rear Base Sprung Weight

Chart "B"

Chart "C"

1976 Camaro Spring Charts

Chart "A", Front/Rear Base Sprung Weight

1976 Chart "B"

1976 Chart "C", Front Springs Group 7.412

1976 Chart "C", Rear Springs Group 7.503