Here goes my 3rd post about this...
So this probably doesn't make any sense, but it's been on my mind for a while. Obviously no aftermarket company makes true OEM springs for these cars, we can get pretty close but obviously not exact. I recently replaced springs in all 4 corners with moog 5662(fronts) and 5665(rear). Here's my before/after height measurements from the ground to the top of the wheel arch after about 200 miles of driving to settle.

BEFORE
​​​​​FD(drivers): 27.25in
FP(passengers):27.75in
RD27.25in
RP:27.5in


AFTER
FD: 28.25in
FP: 29in
RD: 28in
RP: 28.75

It's pretty obvious that the passenger side of the car has some kind of sag, inconsistency, as it has been higher since I've had the car, however it was never that bad until the new springs went in, while a small difference the passenger side is super jacked up looking. Before anybody asks YES I CLOCKED THE SPRINGS CORRECTLY. My first assumption for a fix was weight jacks, since I could always adjust them on one half of the car to level, this makes too much sense. However I'd like the idea of perhaps getting used/low mileage stock springs and just calling it a day for now. Id like some kind of second opinion on this, and maybe if it's worth it?
IT gives some kind of peace of mind having stock springs, however the turnout could always be different for all I know. I'm sure everyone is gonna think this is a stupid idea but I'm impulsive, that's why I drive this car and not a sensible 4cyl. Any thoughts would be helpful.

 

Were the springs you replaced not your stock springs? Because I'd think a TTA would've had WS6 springs. At 33 years old, they're still probably firmer than the Moog springs, and they obviously provided a lower ride height than the Moog springs. Why not reinstall them? They'd be what you're looking for: used WS6 springs. Or get some lowering springs or weight jacks.

 

I put used Z-28 (which I think are the same as WS-6) springs in My 'bird. I didn't like how high the front sat, so I cut a half-coil.
L.F. is 27-1/4", R.F. is 27". This is without the A/C compressor or hood installed. The rear has the stock springs and sits at 28-1/4"...

 

Didn't want the springs sitting around since I have a hoarding problem as it is so I just threw them away. Hindsight is ALWAYS 20/20. I figured since they are generic ws6 springs it might be worth picking up a used set and new powdercoat.

 

Hopefully I won't have that issue if I end up getting used springs. It seems like the 3.8 settles out like a heavy v8, definitely not a light one for sure.

 

I'm not sure what you're looking for, are you trying to duplicate stock ride height, stock spring rates, lower the car, level it from side to side?

So first, most stock springs have sagged horribly in the last 30-40years. Typically the lighter ones sag more than the stiffer ones, but almost nothing that you see is "stock ride height." like these things looked in the 80s. There seems no consistency in sag either, not miles, sitting... My current '87 still has stock springs (I've posted pics and the spring tags here before) that are as close to not sagged as I've seen, and I can't really explain it, the car has 122K miles on it, and there is nothing different from most of the others that have sagged a bit. It's a WS6 TA and it looks like a 4x4, but I'd say it's pretty close to where they started.

As far as what got what springs from the factory- they were weighed and their options were added up and they were assigned spring codes as they went down the assembly line. Pontiacs got slightly stiffer rear-biased spring and sway bar rates than the camaros, making them handle more neutral and making them slightly more aggressively tuned (there was the whole "not competing with corvette" thing and that Pontiac was known as GM's performance division and slightly more upscale than chevy so they got slightly better everything). TTA's were weird all around, they got 34mm hollow front sway bars where a similar equipped V8 would have gotten the 36mm, but they also had the offset sway bar mounts to clear the intercooler, which I've built sets of for people. The front springs were still WS6 springs but were typically one or so code numbers softer than the V8s would have gotten. The 3.8 with aluminum FWD heads on it should have been MUCH lighter than a typical V8, but they got a little porky anyway because just about everyone shipped with every option available.

The difference side to side, well you've had it with more than one set of springs but typically if you don't see anything else I'd suggest swapping springs side to side and see if it changes, you can also check the same by having corner weights checked. Otherwise, I'd start with looking for things like bent fenders (just about every one of these cars has been jacked by the pinch seam behind the front wheel flattening it, causing the wheel arch to bow up and out, and usually the middle of the fender sticks out past the door for the same reason. I've seen a formula that was off side to side and looked like a very nice car, but if you looked carefully from the back you could see the driver's side rear quarter was sticking out like a front fender that got jacked, and finally figured out that that someone hit it from the back at one point, compressed that quarter and the arch got taller and stuck out more, but you couldn't see it anywhere else. I've seen cracked subframes and trans mounts do the same thing. Back in the day my first '83 TA (also a WS6 car) I measured all the factory pickup points and found that the wheelbase on the passenger side was 3/16" longer and out of factory spec and that also caused it to sit a little higher on one side than the other with the corner weights close to balanced. After more careful looking and measuring appeared to be built that way. At one point I was t-boned in that car by some import that ran a stop sign and hit me right at the passenger door pillar at full speed (it might have been as much as 40 or 50mph), and later when I was checking it out all the factory body pickup points were dead on, both sides the same the 3/16" difference gone, but to get the body panels on the passenger side to line up I needed to put a 3/16" thick shim under the lower door hinge.

It could be dozens of things, or it could have been built that way (the 80s were in no way the pinnacle of automotive quality control), but you're not going to know why without looking around or getting someone competent to do it. We'll never guess here without seeing the car.

 

You bring up some excellent points I haven't considered before actually. I'll take pictures later this month and post them on here to see if anyone can spot something I'm missing, but I'm glad you brought up what you did, I could definitely tell under the car that it had been jacked up in many different places... When the suspension gets done over I'll switch springs from side to side and see if anything changes. Ultimately I want the car to be level, and stock ride height, but knowing what stock ride height is I probably would prefer lowered lol.

 

If your looking for a consistent height on all four corners weight jacks will get you there but if you want to stick to the stock style springs your going to have to go the spring cutting route