I have a 67 Firebird 400 4 speed, and I purchased as a roller. I have completed disassembly and ready to get body work started. I have noticed that I have both traction bars, but only (1) of the rear brackets with stamped number of 9789807 and in need of the other one stamped 9789808.

I have two questions:

1) which side do I have currently (Driver side or passenger side?)

2) What is the difference between the two brackets? If I was to purchase the same part number, would I be able to use it or are they that different they cant be cross used?

All the brackets are different unfortunately. Finding a set of two bars and all the correct brackets is rare. If you are extremely lucky you are missing the one that comes on the cars with only one bar. Those are easier to find. You can mock it up and determine which one you are missing.

I always thought the front brackets, that attach to the body where the front spring eyes are, were different from side to side, but that the axle brackets were the same. I see the two part numbers, but they sure look identical to me. First off, getting both traction bars is a score because they only came on the higher powered cars, like HOs. Are the axle mounts that are welded on intact? It should not be too hard to fabricate an axle bracket from some steel plate. The front brackets are much harder to source or fabricate. Can you show a pic of the axle? And the code?

All V8 manual transmission cars came with two bars. My 326 2bbl 4 speed did. The rear brackets are different too. They are angled slightly in opposite direction

That I did not know. Is it dramatic, or could one side be manipulated to work on the other side? So all V-8 manual cars. My 1967 parts car was a 400 w/HD 3 speed manual. It had both bars. Every day I learn something new about these cars!

Boy, is that true. I have had my '68 for over 54 years and it's amazing how much more there is to know about it.

I recalled a discussion about those '67 traction rods in the Rocky Rotella 1st Gen book. He defines when the '67s got two, one or no radius rods. It is determined by somewhat confusing mix of engine - basic OHC-6, Sprint, or V8; and trans - manual vs automatic; and axle ratio - above or below 3.23:1.

The V8 with manual trans is a good approximate rule of thumb for the 2nd rod but a few exceptions were possible.

The only thing I ever read about them was the fact that the first gens were such a rush job that Pontiac was stuck with the mono-leaf rear springs that Chevy used on the Chevy2 and Camaro. Pontiac quickly realized that an engine/trans/gear combination with any real grunt would cause bad cases of spring wrap-up and wheel hop. The band-aid was the traction bars. By 1968, replacing them with multi-leaf springs solved the problem and the bars were deleted.

Your Camaro comment got me curious.
The CRG has an interesting research article on the Camaro rods. Looks like they struggled with this issue and even tried different designs; round rod then rectangular.
http://www.camaros.org/radiusrod.shtml

A very interesting article. I notice the second design rods looked suspiciously like the Pontiac versions. I always wondered if Chevy did anything similar to our cars. This is the first I ever heard about them adding bars. Then again, I once worked on a 1967 Camaro six cylinder car. They were known for tearing the weak DS motor mounts out. Under a recall, they had added a short length of stranded steel cable with loops at each end. The ends were bolted to the engine and the cable looped around the upper control arm shaft. Quite the band aid, but I have to admit, I copied that fix. I always add a short length of chain from the engine to the upper control arm bolt. It is a 'torque strap' that limits engine twist and saves the DS motor mount. It is just loose enough not to transmit audible vibrations through the frame. This is especially important on a manual trans car.

T Sharp, Here's what the '72 Pontiac Parts Book shows for the rod and brackets:

"I recalled a discussion about those '67 traction rods in the Rocky Rotella 1st Gen book." Just a heads-up: that book is out of print and hard to find. And pricey if you do find it. I emailed Rocky at his site Rocky Rotella and he has a few copies left. Send him an email and he will invoice you with PayPal. I ordered mine and it is on the way. I sure miss his articles in High Performance Pontiac magazine.