[unruhjonny]

First, please try to contain your laughter.

There is a local who changed his 1980 TTA to a pro touring type suspension, and is offering his front and rear springs for free.
They look great.

I spoke to him yesterday and said I would get back to him after checking parts cross reference to see if they would work for me.

In the course of the conversation I learned that his car was a 301T car with the disc brakes - so on that it's a WS6 car;
One could assume that his car would be like most of that time and be fully loaded;
Even though the 301 was lighter than the 400, the turbo and ac should more than make up for the weight savings for the "lighter" engine... so we should be at something comparable - at least that's how it makes sense in my mind's eye.

I have master parts catalogs for the full second gen run, and looked up the numbers used for 1980 versus 1970;

That chart wanted reference to the vehicle weight chart on the door sticker... so that wasn't too much help.
And it had all different numbers.
huh.
Strike one.

I then figured that I could use the "early" springs from this MPC (1977) to compare that years 400 listings against the 1980 WS6 listings.
There was some overlap, but it was still different;
There were less application listings for 1977 versus 1980, but I still consider it a strike.
So;
Strike two.

I am, and always have had a budget, and if I can find good parts that will work for a time, or supplant the need for new parts all together, I am totally open to this idea.

Does anyone have any means of comparing old versus new front and rear spring part numbers?

According to the "new" 1967-1976 MPC I have these are the 1970/1971 springs:

1970
Front 400 = #3982346 (st & non-A/C)

Rear 400 = #482548

1977
Front (T/A 400 & st) = #3988113 or 462509 (over 950lb sprung weight)

Rear (T/A 400 & st) = #481132

1980
Front (WS6 chart; 0-1002 GAWRF) = #3988111
OR
Front (WS6 chart; 1003-1041 GAWRF) = #3988113
OR
Front (WS6 chart; 1042-1144 GAWRF) = #462509
OR
Front (WS6 chart; over 1144 GAWRF) = #426511

Rear (WS6 chart) = #481132 or #480885 (over 1083 GAWRR)

Can anyone offer me any help?
Maybe have a cross reference for a part number vs spring rate, and unsprung height?

The good Mennonite in my sees a way to save money and wants to act on this opportunity.

[Formulabruce]

Ok, IF you want to "drive your car" do NOT ever buy "new" rear stock springs for a 1970, even from Eaton.
If you get 4 leaf, they will still need to be De-arched.
In 1970 the rear had 2 different springs, so dont use a part number for springs till you get to 1973, where it is the same both sides.
Used springs from an 80 T/A . Great score, and I would and have run them. I have bought a few sets from Frank, when he will sell springs, he doesnt like to.
The 80 springs will sit a inch lower than a used 73 spring, but will ride and handle better.
Front springs.. Used, if car was level and in nice shape are a good deal as well. I have run 1980 front springs in my '71 and I loved them.
Why bother with a stiff ride and too much height if you dont have to.?
Pontiac changed rear springs and ratings in the early 70's due to two factors
1. The roads were begining to be "crowned" during paving, for run off. This affected bias ply tires and so spring rates were tried to compensate.
2. The advent of the radial tire and ( RTS).
Conclusion, You WILL run radials, and you Will be on modern roads with crowns. The '80 springs are great find if not rusty .
Part numbers are not that useful in a used spring market. The application can be , and you have that.
Grab them.
My Relatives, Mennonites make the best Sho-Fly Pie !

[unruhjonny]

Thanks Bruce!!

[Rocky Rotella]

Originally Posted by unruhjonny

In the course of the conversation I learned that his car was a 301T car with the disc brakes - so on that it's a WS6 car;

Unrelated to Bruce's comments, which is first hand experience using various springs in application, don't assume that WS6 was required with the 301 Turbo engine based on your quote above. I did too, but since learned otherwise!

https://www.pontiacv8.com/blog/2021/...s-am-tidbits-1

[Formulabruce]

/\ /\ Now there is some info! I was still working as a ASE tech at a Dealership in '80 and '81. I set up many cars when it was slow in service. I saw stuff that I thought couldn't be right, but there it was. I seem to recall a customer ordering white walls on his Formula and when I set it up, it had 15x6 rally, not 15x7. Wish I would have saved all the build sheets I found sticking out from the rear of front seats and barely under the carpets. I went to a minor service and operation class on the th350-c but never saw one on a T/A, and there were pissed off customers that couldn't get a 400-4spd, or a 4 speed, or even a 3 speed stick in 1980.

[unruhjonny]

I really had no idea that the WS6 was separate from the disc brake rear;
I had thought that the disc brake rear end was the single indicator of WS6!?

I heard back from this fellow, and have made plans to be at his place late this afternoon to grab anything he has to offer.

Thanks for the feedback guys!!

["QUICK-SILVER"]

Originally Posted by unruhjonny

I had thought that the disc brake rear end was the single indicator of WS6!?

I've always looked for the lower control arm brace to see of it's WS6.

Don't know if that's good enough
Clay

[Rocky Rotella]

WS6 included J65 disc brakes, but J65 was its own option from 1979-1981, so there are rear disc brake cars out there without up-level suspension.

Then in 1979 when issues arose with rear disc brake production, Pontiac released the WS7 option, which is basically WS6 without J65 included. One might say that WS7 was essentially the WS6 from 1978. So there are later Firebirds with up-level suspension without the disc brake rear axle.

[HWYSTR455]

One thing to note, which I picked up somewhere along the way, was that the control arm bushings had a few different varieties, depending on the application. WS6 cars got a higher durometer control arm bushing (leaf bushings too), which was used in calculations for 'total' spring 'rate' or 'action'.

As all know, the sleeve in the center of OE type control arm bushings have 'teeth', and bite into the frame tabs, preventing rotation of the sleeve in operation. And, due to the materials' resistance to twist, impacts overall 'rate'.

Many complain after swapping control arm bushings that some handling differences are noticed. Especially when switching to poly or the like (which don't have teeth in the sleeves). Theoretically, the only way to regain what was lost is by going to a higher rate spring.

Those bushings from what I understand is a Pontiac-only approach, and played a role in why firebirds handled better than camaros.

As for springs, the problem with aftermarket springs is that they have a wide tolerance, and can be as much as 15-20%, or more. That can be a difference even in the same set (hence the 'lean' complaints).

It doesn't stop there either, because many service replacement parts' listings are generic, and cover say, all F-bodies, or may even include X-bodies. Springs are then manufactured in a 'range' to cover more applications, further moving the original target.

Even factory service parts can be grouped and manufactured to cover more models, and reduce total cost of manufacturing, since by law at least 7 years of service parts need to be offered.

So, when someone says 'so-and-so made factory spec springs that I got' I have to laugh. Truth is, there's no real way to determine that, and would be lucky to even get close.


.

[unruhjonny]

I have understood about the generic nature of aftermarket springs, and knew that I would eventually have to open this can of worms.

I knew that that the originals were all different, and that OE generally worked better than aftermarket - which is why I figured it was worth going this route, and getting some sort of feedback from the knowledgable people here;
I expected the feedback to be more in line with XX will be #300 stiffer than the OE springs for your car, and make it ride higher;
I didn't expect the proverbial green light that I received.

About why this was a pending "can of worms";
I wasn't to surprised to find upon disassembly, that both of my car's rear leafs were broken;
I was surprised to find one of my front springs broken - it was broken just enough, that it stayed in place, and only fell apart into two pieces after removal.

I pulled (what was probably original to my car) spiral shocks off in 1998 or so;
Both were shot;
One shock did nothing absolutely nothing - you could shake it up and down, and the rod would move that easily.
The other shock offered resistance in both compressing or expanding, but would not rebound to when compressed... so I tossed them both at that time.
Had I know that the repops are garbage, and they could get rebuilt I might have held onto them.
I installed new sensatracks in 1998, and later added what I coined as "hillbilly risers" - essentially a bolt with a curved head, and a corresponding curved sleeve and nut - it was installed in the spring, and essentially held it a little more open.
I think the 'hillbilly risers' are still on my cousin's Trans Am.

Anyway...

I expected I'd be getting EVERY-THING;
And was pleased to see here in the last year or so one thread about one company offering good replacements that wouldn't make our cars look like 4x4's - which seems all too common when those generic springs are installed.

I hope this turns out as well as has been suggested.

[HWYSTR455]

Well, the rate of a spring isn't typically the character that makes a car sit high or low, it's the height of the spring. Or arch, when it comes to leafs. Now if you get a spring that is the same height as the spring you have, at a higher rate, then that can make a car sit higher.

There are manufacturers that make and sell quality, close tolerance springs and leafs, but you need to know what to order. That's where some of the aftermarket 'tuner' type companies come into play. Basically, someone took the time to figure out height, rate, etc byt trial an error, and then marketed them.

Those types of shops also know how to compensate for different types of bushings, as well as balance characteristics of spring rate/sway bar diameter. That's why you see a number of people recommend getting a 'kit', or 'matched' set of springs/leafs.

Corner weighting a car is one of the methods used to help come up with a 'matched' set of springs.

Ride height can change the requirements of spring rates, which is often overlooked. Like if you raise the rear of a car, it loads the front springs more, and visa-versa. Which too lends to why many recommend a matched set or kit.

OE type 'toothed' bushings change shock & spring requirements. That's why many complain once they changed to something like ploy bushings and nothing else, and technically, it has nothing to do with the bushings per se.

Although I don't use them, I have recommended a number of people to use PTFB spring kits, they are a good balance between stock and 'soft' autocross type setups, and are affordable. A member here somewhat recently installed their' springs & leaf kit and was very happy with ride and ride height, and they are not expensive.

http://www.pro-touringf-body.com/Suspension_kits.html

Another way you can determine what you may like is by asking owners at cruises or shows, find a car you like the way it sits and ask what they used. That way you have an actual physical reference.

I personally use Global West stuff, but it's a little more expensive than most. I've always had expected results, and if I wanted to fine tune it, they worked with me, even on returns. Doug is a Pontiac guy, so there's a good reference there.

Many lump all F-bodies together, and although there is some truth to that, you can end up with a setup that was more for a chevy small/big block. What many overlook is that the endura nose cars don't compare to the chevy counterparts, which leaves the buyer disenchanted.

PTFB too is very familiar with Pontiacs, and they ask that you call when ordering a kit. You can talk to them about weight, ride height, etc, and they have you covered.

Most tuners use the same place for springs, Landrum has very tight tolerances, and measures every spring before shipping. Most do have them make springs to their' specs though, not off the shelf stuff.

If you want some technical background, they have some good info on their' website about springs & leafs:

Their' leaf offereings:

https://landrumspring.com/products/l...-leaf-springs/

Technical:

https://landrumspring.com/technical/

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[unruhjonny]

If I was to order anything new, I would probably be looking for the exact OPPOSITE of a pro touring (or handling) spring;
I would want a lower spring rate to permit quicker weight transfer so that my car might launch like this car:



I just picked up these springs, and they look really good.
If they work even as a stop gap to permit me putting off buying the Eaton three leaf #ML3595 (GM #482546; rated at 103lbs) springs as suggested by Bruce in THIS thread, then so be it.

I will look into those links though;
From a cursory glance their (rear) springs start at 150lb spring rate.

Cheap used parts after all are still cheap used parts - not necessarily the cure-all.

And just for groans of how bad mine were, may I present a side by side comparison of mine versus these ones from a low mile Georgia 1981 TTA:

[Formulabruce]

Doug at Global West is a great Pontiac guy, and knows his stuff. ( HWYSTR455 is correct)
I personally love their Del~A~ Lum bearings for the front a arms and rear spring shackles and front mount.
This eliminates the "tooth" and allows the arms to work more like struts, which are WAY faster to react to road imperfections.
That said; Your Original Shocks were a 1 way valve shock. Easy to Compress and hard to pull apart.
repop original shocks are museum only pieces...
New shocks have 2 way valves and are gas charged which makes them faster and work well with Global west bearings.

[HWYSTR455]

So one has to remember, in OE config, the bushings are part of what gives you the total or actual spring rate, or, 'feel'.

That impact, for example purposes, could add @ 50 lbs to the total 'rate', and when you go to free-articulating bushings, like del-a-lums, you need to compensate for the 'loss' of rate from where you started.

More example: If your' front springs are like #350, and you go to free-articulating bushings that reduce by #50, you now need a #400 spring to be back to where you started.

The nice thing about a free-articulating suspension is you can now more easily tune the suspension with spring rates and shocks. The shocks now actually get to 'work' as intended. (Though you do need to upgrade to better shocks to take full advantage).

So it's not very accurate to say that by going to a higher rate spring than OE it will ride like a 'dump truck'.

With that said, it is possible to go too light or too heavy on spring rates. Generally, it's personal preference, and how you intend to use the car for the majority of the time, all else will be a compromise. Or, you can say, it's a matter of what areas you are will to compromise in and is acceptable to you.

If a spring is too soft, you will give up handling, but may gain in straight line acceleration 'launches'. I say 'may', because if you go too soft, you will have to combat tendencies to wheel hop.

It is possible to have a great handling car and still be able to launch. There are other 'settings' that can be done to improve launching, anti-squat is one of them, another is to lengthen the second leaf up to the center of the front spring eye. It's about knowing the impacts of changing one area and how it effects other areas that helps you find your happy median.

And there are different approaches, such as the Herb Adams/Guldstrand 'controversy' of 'soft springs big bars and stiff springs/small bars. It comes down to a personal preference, both have used their' own approach successfully.

The PTFB '1LE' spring kits were made based off the WS6 cars, and generally are meant to be used with OE type control arm bushings. If you go to free articulating bushings, then it would be best (IMO) to step up to the 'GT' package, or the 'GT-Pro' package. If you look, you will see the 'GT-Pro' package comes with adjustable shocks, which is a good hint to where the additional tuning will lay.

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[Elarson]

Looking for a baseline. Does anyone know the rear leaf spring rate used on the Trans Am from the factory? I'm assuming there were subtle differences year-to-year?

Thanks,
Eric

[FrankieT/A]

Originally Posted by "QUICK-SILVER"

I've always looked for the lower control arm brace to see of it's WS6.

Don't know if that's good enough
Clay

My 78 WS6 car had white hard plastic stabilizer link bushings when my car was new. Of course, over time they split and needed to be replaced. As everybody knows 78 WS6 did not have 4 wheel disc. Now the question becomes, when you find a used car or one in the junk yard, the indicator for WS6 for me has always been to look for the lower control arm braces as well. I know that 4 wheel disc is not an indicator of WS6 in 80 and 81.

On my 71 I replaced my rear springs with 79 WS6 springs and when I layed them side by side upside down the the WS6 had a couple of inches less arc. Standing on both at the same time one foot on each you easily see(or feel) that the WS6 was much stiffer but shorter. When I put them in they gave me perfect stance. My fronts are aftermarket so a whole other story.

[HWYSTR455]

WS6 cars, at least in the later 70s, had larger sway bars. Also, I know the 79-up ones got the wider snowflakes, which has an actual lip on the outside of the wheel.

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[HWYSTR455]

Thing is, if you're shopping for a WS6 in the boneyards to get the springs out of them, I would say that's a waste of time, the springs/leafs will be trash after that many years.

The nylon end link bushings were at one time I believe available from Herb Adams VSE and/or H-O Racing. They make the bar 'react' faster, by having less deflection.

Herb Adams also had the spherical end link conversion, where he cut off the ends of the bar and welded them at a 90 degree angle, and used 90 degree end links.

To comment on sway bars that don't move freely, there were a few oddball size bars out there, and have seen many use the wrong bushings. I've seen folks try to tighten those down to the frame so hard that the threads would strip out of the frame.

Also, an upgrade from OE, several offered rear drop links that had a flat plate on the bar end, so you could use standard from bar bushings, and not those crappy round things. The ends of OE drop links would break after cycling them a number of times too.


.

[FrankieT/A]

Originally Posted by HWYSTR455

WS6 cars, at least in the later 70s, had larger sway bars. Also, I know the 79-up ones got the wider snowflakes, which has an actual lip on the outside of the wheel.

.

Not correct...'78's got 8" wheels also, but the outer lip was painted and the corner was really sharp.

[FrankieT/A]

Originally Posted by HWYSTR455

Thing is, if you're shopping for a WS6 in the boneyards to get the springs out of them, I would say that's a waste of time, the springs/leafs will be trash after that many years.

The nylon end link bushings were at one time I believe available from Herb Adams VSE and/or H-O Racing. They make the bar 'react' faster, by having less deflection.

Herb Adams also had the spherical end link conversion, where he cut off the ends of the bar and welded them at a 90 degree angle, and used 90 degree end links.

To comment on sway bars that don't move freely, there were a few oddball size bars out there, and have seen many use the wrong bushings. I've seen folks try to tighten those down to the frame so hard that the threads would strip out of the frame.

Also, an upgrade from OE, several offered rear drop links that had a flat plate on the bar end, so you could use standard from bar bushings, and not those crappy round things. The ends of OE drop links would break after cycling them a number of times too.


.

Anything from Herb Adams was aftermarket. WS6 cars had nylon from the factory. Plenty of aftermarket company's offer nylon. Let's not forget Herb designed (or should say Spec-ed the suspension for 1st gens and second gens) the suspension in the first place.