Frequently Asked Questions
Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked and answered on FGF. Special thanks needs to be given to all the FGF members who took the time to respond to other member's questions.
Codes - Drive Train Codes
Short answer: A car is considered “numbers matching” if all the part numbers and casting codes are correct and pre-date the car by the usual 1–3 months. Use the year-specific drivetrain ID pages on FGF as your guide:
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Content last modified: June 13, 2026 at 10:06 am
Short answer: Pontiac rear-axle housings can be identified by year using their date codes, stamped codes, and a few physical features. The 1969 axle ID codes differ from 1967–68 — the full table is below.
Identifying features by year:
- 1967: the center section has the loops for A-body control-arm bushings plus leaf-spring perches and factory traction-bar brackets; a date code is cast into the center section.
- 1968: dropped the control-arm loops and traction-bar mounts, but used the same codes as 1967.
- 1969: the date-code position moved to the other side of the center section, and flattened spots were added on top of the axle tubes where the snubbers meet (1967–68 have none).
- All three years carry a 2-letter stamped code about 3–5″ to the left of the center section, on the rear of the left (driver-side) axle tube — often hidden behind the steel brake line.
When identifying a rear end, check the cast date codes (same style as engine parts), the axle code (rear of left tube), spring-perch depth (1967 Monoplates are shallow), the extra traction-bar brackets (1967 only), and the flattened spots on top (1969 only).
1967, 1968, and 1969 Axle Identification Codes |
|||||||
|---|---|---|---|---|---|---|---|
|
Ratio |
1967 |
1968 |
1969 |
||||
|
Std. Diff. Code |
Lock Diff. Code |
Std. Diff. Code |
Lock Diff. Code |
Std. Diff. Code |
Lock Diff. Code |
||
|
2.56 |
XB |
UN |
XB |
UN |
YB |
ZB |
|
|
2.78 |
XC |
UP |
XC |
UP |
YC |
ZC |
|
|
2.93 |
XD |
UR |
XD |
UR |
YD |
ZD |
|
|
3.08 |
XE |
US |
XE |
US |
YE |
ZE |
|
|
3.23 |
XF |
UT |
XF |
UT |
YF |
ZF |
|
|
3.36 |
XG |
UV |
XG |
UV |
YG |
ZG |
|
|
3.55 |
XH |
UW |
XH |
UW |
YH |
ZH |
|
|
3.90 |
– |
UX |
– |
ZP |
– |
ZK |
|
|
4.33 |
– |
UY |
– |
ZR |
– |
ZM |
|
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: On the Billing History card, the axle-ratio sales code appears in box 74 (1967) or box 37 (1968). The codes are the same both years:
| Code | Ratio |
|---|---|
| C | 2.56:1 |
| D | 2.78:1 |
| E | 2.93:1 |
| F | 3.08:1 |
| G | 3.23:1 |
| H | 3.36:1 |
| K | 3.55:1 |
| P | 3.90:1 |
| S | 4.33:1 |
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: The axle-ratio sales code on the Billing History is in box 74 (1967) or box 37 (1968). The codes are the same for both years.
| Code | Ratio |
|---|---|
| C | 2.56:1 |
| D | 2.78:1 |
| E | 2.93:1 |
| F | 3.08:1 |
| G | 3.23:1 |
| H | 3.36:1 |
| K | 3.55:1 |
| P | 3.90:1 |
| S | 4.33:1 |
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: A few weeks’ gap between an engine’s date code and the Fisher Body trim-tag date is completely normal — nothing to worry about. The rule of thumb for drivetrain parts is roughly 2 weeks to 3 months before the body build date (about 6 weeks is the usual maximum), and generally not after, though exceptions exist.
- The trim-tag date is when the body shell was assembled at Fisher Body — not final assembly. The final date is the “Invoice Date” on the Billing History (when the car was certified to ship).
- Worked example: a body shell scheduled the 4th week of October 1967 (the 23rd–27th), with a “WK” block (date code I177) cast Oct. 17, 1967 — cast on a Tuesday, likely assembled around the 20th–23rd, then a couple more days to reach Lordstown for final assembly. So it could easily have gone into a body built that same week.
- Low-production cars were often built in batches, so many of the same model/color/engine ran through within the same period.
As always with date codes, there are no absolutes — inventory control 30 years ago wasn’t what it is today.
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Content last modified: June 13, 2026 at 10:06 am
Bulletin 68-I-37 — Pontiac Motor Division Dealer Service Information Bulletin, Section 5, dated January 31, 1968. Attention: Service Manager.
Subject: 1968 Tempest Rear Brake Drums.
Short answer: Some early-production 1968 Tempests were built with Kelsey-Hayes rear brake drums stamped “F” instead of the specified “KH” identification. Future drums will use the combined code “KH-F.” All three codes (“KH,” “F,” or “KH-F”) represent acceptable Kelsey-Hayes drums — a variation between right and left drums is not a concern.
Pontiac Engineering has advised that certain early-production Tempests were built using Kelsey-Hayes rear brake drums coded with identification letter “F”, rather than the specified identification “KH”.
Future Tempest rear drums manufactured by Kelsey-Hayes will incorporate the code letters “KH-F” as an optional identification.
Since Kelsey-Hayes drums with any one of these codes (“KH”, “F”, or “KH-F”) are installed in production, there should be no cause for concern regarding the variation of code between right and left rear drums.
Content last modified: June 13, 2026 at 10:06 am
Short answer: The two-letter axle code is stamped on the driver’s-side axle tube, facing the rear, roughly 6″ from the differential cover (near/to the left of the brake clip). It’s often rusty — expect to wire-brush/sand to read it.
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Short answer: Per the 1967 Firebird supplement, the eight axle ratios are identified by a two-letter code stamped on the rear of the LH axle tube:
| Open | Ratio | Limited-Slip |
|---|---|---|
| XB | 2.56 | UN |
| XC | 2.78 | UP |
| XD | 2.93 | UR |
| XE | 3.08 | US |
| XF | 3.23 | UT |
| XG | 3.36 | UV |
| XH | 3.55 | UW |
| — | 3.90 | UX |
Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.
Content last modified: June 13, 2026 at 10:06 am
Content last modified: June 9, 2026 at 7:10 am
