So, now I know most of my car is frankensteined, it's only fitting to work out what rear end I have. I don't believe it to be original...

Here are some pictures if the shape of it helps, the gasket/cover shape is interesting:






It's now painted, but I'm certain there were no codes on the tubes, just on the central casting. These are:
B157 (casting is a bit hard to read)
9783393

The ratio is slightly more than 2.5.

Definitely a proper '67 BF rear with the Tempest Upper control arm bushing eyes, brackets for both OEM traction bars and mono springs.

So no 2 letter code on the rear of the driver's side axle tube? Then the only way to get the rear axle ratio properly will be to pull the rear cover and count the gear teeth.

41 on the ring, 16 on the pinion. So, 2.5625.

Quite sure that there wasn't any code on the tube. I could've of course missed it and painted over, but I don't think so.

The only code on the axle is on the central casting:

Which reads B157 on top and underneath: 9783393.

I read somewhere that the rear end shouldn't have a casting code here??

The main thing that casued me to suspect it is not original is when I ordered (2 from 2 different places, forgetting I'd already ordered one) the gasket for the cover (for presumably the stock '67 10 bolt) and it didn't fit - the replacement was completely round, where mine has two cutouts in the sides... like this (sold for a '70-'81):

The scallops on the sides are the way to tell the 8.2 inch BOP 10-bolt from the Chevy axle. The Chevy reaf cover is oval. The 70 and up 2nd gen Firebirds used the 8.5 inch rear end.

Oh, OK, so it's probably the original rear end? The axles are retained by 4 bolts at the brake ends, not c-clips. It was just the gaskets not fitting that worried me.

Any idea on the casting code?

I might scrape some paint off and look for a tube code, as I've got some other bits to paint anyway...

Casting code will tell you nothing. 41:16 is a 2.56, used on a 230 1 bbl or 326 2bbl 2 speed auto without A/C. Neither of those used dual traction bars, so there was likely a gear swap at some point, or a traction bar added. The 2.56 housing's code would be XB (open) or UN (Safe-T-Track).

That is a pure and proper setup for a '67 Firebird with dual traction bars.

In his photos he only has 1 traction bar that I can see. If so, then the axle and the ratio would fit with his original setup of a 326 2 Bbl without A/C

I would have to guess with the A-body style upper control arm mounts, and the leaf spring mounts & traction bar mount, the someone had the axle made up to replace the original axle. They used the center section of the A-body axle, probebly had new tubes made or the correct leanth to fit it (would explain the lack of codes on the passenger side axle tube) and then welded on the single leaf & traction bar mounts to make it bolt up to the car.

And with your car being in the UK, I think the axle was damaged in some way, and the A-body axle was all they had available to work with.

Just a guess on my part.

Thanks all for the input...

I do only have the one traction bar, which is stock for my 2bbl 326 auto non-AC.

Did the Tempest and Firebird not share rear ends, hence the unused control arm mounts?

The car was brought over to the UK by me about 18 months ago, so any work to it will have been done in the US.

Here is a picture of the original rear end from my '67. It is identical to the one in your picture. Mine is a 326-2 as well.

The c clips are on the inside of the housing not on the ends. It will be on the inside ends of the axle shafts. Nice looking rear end. LOL

It's my understanding that the stock '67 FB rear end does not use c-clips, but instead the axles are retained solely by bolts at the brake end of the axle housing tubes. May be wrong though...

I might be wrong also. Can you move the axles in back and fourth about a 1/16". I'm still learning to. LOL

A BOP rear should not have C clips. It should have a retaining plate and bolts.

The rear end with the inside upper trailing arm mounts is correct for the '67 FGF.

There was a delay in getting the correct FGF center casting in time for initial production, but it was corrected in 1968 (probably in late-production 1967). Pontiac simply borrowed from the A-body parts piles and fitted new tubes and added spring perches. Nothing wrong with what you have.

-AS Quenton staed...The rear IS CORRECT...with the upper control arm mounts. I have seen this many time in early Firebirds.
-ALL 8.2 Pontiac rears from 1964-1972 has bolt in axle retention
-Axle code could be on the back of the driver side axle tube also between the spring perch and the cast center section. (2 letter code)
-Rear gasket confusion: The pontiac rears all have the scalloped cuts at 3 and 9 o'clock areas. The 8.5 confusion comes in with the Buick 1971 1972 rear that had a cover that was very similiar with 3 and 9 0clock cut outs BUT is slightly different cover bolt pattern (REAL close but NOT...it is 8.5 only from 1971 9172 1973 1974 B O rears also using the bolt in axle system.)
C-clip rears were ONLY chevy from 1965-1972 era. Including the 12 bolt chevy and 10 bolt chevy.

Hope all this info helps.

In my option you have the original rear for your firebird.

Jim