[Formulas]

Its been a long time since i bought shocks for my bird.. i have the old white KYB gas adjust in there now and i believe they are tired.

With that being said iam not up on the very latest shock technology i was reading a bulletin board somewhere and the consensus there was for good overall street and high speed handling the Bilsteins sports were good.

What i have on this particular car is stock replacement springs up front higher rate rears and lowered a inch or so in back i don't like how it rides or looks currently

So i am entertaining the idea of news springs and what i am looking for is the next level up from stock on both springs and shocks without it riding like a covered wagon and want it sitting level

So anyone happy with such a setup and what does it consist of ?? thanks..

.

[Formulabruce]

The car set about an inch lower in the rear from the factory, and with correct rating spring ( I prefer a 126) you'll get a good ride and better handing than the ass in the air ( that old controversy over "stance" )
I like the way Craigs car sits , but his is not stock springs, and I do not know the ride quality on stock 15 inch BFg's
Cheapest is use stock Eaton springs and do NOT get a HIGH rate or youll just be building a burn out mobile. I always get ( Rear 4 leaf) the 126 rating, which is Esprit I think, but when new is a bit stiff. Eaton also sells the fronts in your choice and you can select your car and options from their list.
Bushings, you can get either poly from Energy suspension, and grease them well. OR you can by Delalum Bushing kits from global West that make your bushings all a "bearing", which gives your (Front A arms and rear) suspension a much faster reaction time to road bumps, making your new shock choice much more valuable, and they can work as designed.
Car will sit level unloaded and ride and handle well
Biggest tip .. If you do NOt use a Delalum Bearing kit, Do NOT tighten any supsension bolts till the loaded car is on the ground and the suspension is moved up and down , rolled around a little . This will eliminate a high ass end and same in front.
With the bearings its done differently , and all the parts move and swing easily.
I do have part number for the bearings and the energy bushings if you want Ill dig the up. Eaton is easy spring choice and make SURE the rear is 4 leaf.. Many many places will say ( its same as camaro) its NOT.. Good luck
Some folks just HATE the Assembly manual, but here ya go!!

[keith k]

I would go with everything in the suspension stock, with the exception of good dampers (the Bilsteins are a good choice), and really good tires (which likely means you'll need to run larger than stock wheels).

Stiffer springs will only kill the ride. The body/chassis on these cars isn't rigid enough to take advantage of anything much beyond the stock rates, IMO, unless you're planning to stiffen it.

[Formulas]

what was the highest spring rate stock for our birds, trans am no air con.?

How about BBC. Camaro 2nd. gen Z-28 springs cut for height

I already have poly urethane bushings and I have run front 700lb. GT springs from guldstrand engineering with 1.1/4 sway bar up front and a 7/8 bar in the back with 160LB. rear leafs with a sub frame connector and solid body bushings
The car felt stable at any speed no floating around at 130 and the steering was great at that speed as well

wheels and tires were my limitation at that point and it rode like a truck I couldn't complain as I built it like that

so I have been around the block sort of speak I wont go stock rubber bushings again as I put them in one of my cars and they degraded in only about 3 years

I just want that fine line where you can tell there is some capability there over stock but no dump truck feel thanks

[bird72]

Cornering and launching are two different perspectives and a good old bird is a compromise on both. Super stiff rears hop and burn out too easy. My personal unsubstantiated opinion is big sway bars, softer rear springs than TA, and good shocks. Will corner flat and bumps and launch better. Not spot on restoring a rare car to spec leaves some options for this stuff.

[Formulabruce]

Lets look at some facts
1. When you get GM ASE certified on Suspension in the 70's, the FIRST thing that's taught is that "Tires" are part of the suspension. Seemed simple back then....
2. RWD car suspensions are built for RIDE AND TRACTION...Even on Firebirds, handling is a last concern. IN Pontiac, "Drive- ability" is Job #1, and accounts for 90% of service work
3. Suspension Bushings, front and rear.
A. The factory rubber AND the poly bushings work on same principal in the Front and the Front part of the Rear leaf springs, a 15% "Twist" , plus the spring rate , is basically your stiffness, Which is a SLOW to respond suspension. ANY stronger springs will make this even slower, and a much harder ride.
B. Lowering the car Will require stiffer rate springs to avoid a bottom out condition, and with the Rubber OR Poly bushing, you have a much more Bumpy ride. Throw on wheels and tires with NO side wall and you have your 3/4 ton truck ride.
C. To accomplish ANY spring Increased rate one must make the suspension More responsive ( IE: FASTER)
D. Faster, and stock. The ONLY way to improve suspension reaction time ( aside from putting on gas shocks on a stock suspension) is to get RID of the "Bushings" and put in Bearings. Bearings allow your suspension do what it was meant to do, MOVE. Allowing this movement makes the wheel stay on the ground more, and also, with good shocks helps absorb a certain amount of the bumps.
When you convert to a bearing set up, your suspension comes Closer to a "Strut", which is where suspensions went after second gen's.
many cars I have seen with Polys also install them on the sway bar. MOST I have seen, the sway bars WOULD NOT MOVE if you disconnect the end links, because they are SO TIGHT.
Global West has some great videos to Explain the "Bearing" and how much it can help with a stock suspension. Here is a short video
Part number from Control am UPPERs is #1014 ( You do NOT have to buy their control arms assembled)
https://www.youtube.com/watch?v=dUQbcyVINL8

[Formulas]

I went with Moog 8000 front springs they are in between the weak original and GT springs I have experience with after I finish putting the car together so all the weight is there I will probably have to trim them a bit for desired ride height since I'm ditching the A/C and going front fiberglass bumper

[eaglesan13]

I would be interested to know what your ride height is after you install the springs (and before your trim them). My 71 t/a sits too high and I want to bring it down a few inches, but I don't know what front springs are in it.

Originally Posted by Formulas

I went with Moog 8000 front springs they are in between the weak original and GT springs I have experience with after I finish putting the car together so all the weight is there I will probably have to trim them a bit for desired ride height since I'm ditching the A/C and going front fiberglass bumper

[Formulas]

You already have the springs remove cut them reinstall and go from there .. with a cutoff wheel... In my experience it's real hard just to buy off the shelf springs and end up with the exact ride height you want unless your front end weight is factored in either by being bone stock or actually weighed

[Formulajones]

The only issue I have with cutting coil springs to lower the car is that you also inadvertently just changed the spring rate. In layman's term, it'll get stiffer as you make it shorter, and hurts the ride quality.
I helped a neighbor do that to his 67 S code mustang because he thought it was too high in the front. He got the ride height he wanted but it rode like a dump truck afterwards.


Correct front springs used to be determined by the amount of options a particular car had. Here is a chart GM used for the 69 Camaro. As you can see as options piled up, and weight changed, it would bump up the spring requirement. I know a few that have used a chart like this to duplicate a stock type spring and get the ride height and ride quality they desired.

Maybe something like this is available for the birds? Or something like this may cross over.

I can tell you for certain my 70 Formula (non AC) has the exact same front springs that GM used in the 70 Z/28 Camaro. Same sticker codes.

[Formulas]

This isn't rocket science a set of springs are in a car the problem is ride height cut to desired height drive see if your happy or not the money is spent already .. original stock spring rates pretty much suck to start with. . My car will have a fiberglass bumper no A/C or heater and quite possibly the battery in the trunk pluss I like a car that doesn't bottom out on a popsicle stick so likely my data won't apply to the bone stock crowd

[Formulajones]

Actually there is a science to it with various formulas.

Just buying a spring with the front too high, which means the spring is too stiff, and then cutting it to the desired height is the complete wrong approach I'm sorry to say. You may find your height, but you're also making an already too stiff spring even stiffer. Then ride quality is going to suck.

You can have your height and your ride quality at the same time with a correct spring.

[Formulas]

Thanks for your help Jones but right now your preaching to the choir I have what I need you may wish to PM Eagle he seems to have a spring already paid for and installed the next logical step to possibly make the most out of his current situation would be remove cut reinstall and evaluate.. . I personally have never said anything in this post about what happens to a spring when you cut it your assuming to much..

[Formulajones]

I'm not worried about you, But I do feel it's necessary to warn the OP of the consequences of cutting coil springs. Best decisions are made when all the facts are presented

[Formulas]

I am the OP you're stuck on giving coil spring lessons that you overlook the fact that someone that chimed in has already bought and paid for springs installed them in order to POSSIBLY save his investment his next logical step should be cut the fricken springs to get his desired ride height and see if he can live with the results period.. His next logical step after that would be to purchase another set based on actual front end weight along with desired ride / stance characteristics. .. Myself I recently found my receipt from when I bought my coils from Gulstrand in 1982 they were actually 650 lbs rate that I had to cut for ride height this time around I wanted something in the middle between them and weak stock set up and the 650's... Thanks for all the help

[Formulajones]

It's important to express all angles so someone doesn't make the same mistake. Especially for all those reading. The correct spring is out there if you do your research. I posted a small example.
Sometimes we buy incorrect parts. We chuck it up as a lesson and move on. Sometimes that's an expensive mistake. Springs aren't that expensive so.....in this case buying a correct set is a better alternative, and relatively easy to find and purchase. I would never recommend cutting, my customers would have a fit. If you want to cut them and don't mind the increased spring rate and rough ride, then by all means.

[BobC]

Has anyone tried the Ridetech Streetgrip system?

[Zyman]

Originally Posted by BobC

Has anyone tried the Ridetech Streetgrip system?

Try posting the question here: http://www.pro-touring.com/forums/21-Suspension

[unruhjonny]

I am going to bump this thread rather than make a new one, because from my searches, this seems the best/most relevant thread to me.

I looked up the Eaton springs:
Eaton 1970 Firebird Formula 400
These would be appear to be my factory units - it looks like the OEM springs (according to them) are left-#126 (w/o 15" tires) & right-#103 (w/o 15" tire);
My MPC doesn't show spring rate, only part numbers;
Right = 482546
Left = 482548

Now, I am not concerned about building a corner carver, only that I get stock ride height, and maximize possible traction.

I would love for my car to look something like this:

... or maybe a bit lower like some period press photos showed them;
and I DO want it the sit a little lower in the back...

(I can't help but feel there's another picture of this car, maybe b&w, which has a different angle that shows the rearward rake better.)

Is there any reason why I should consider going to #126 on each side - which is what Pontiac appeared to do part way through 1972, and for '70-72 Trans Am's (which came with 15" tires).

also, since coil springs were mentioned in this thread;
is Eaton a good choice?
I also saw that between NPD, Ames, and CI, all offer coil spring spacers - now unless there were ones which dissolved over the past fourty-eight years, it looked like my car never had them;
Should I have them? (my gut says no)

I pulled the original shocks off my car back in 1998;
these appeared to be the original coil springs (they had (?)aqua-blue tags on them);
I had 1 original upper ball joint...
I say all this to illustrate that in spite of it being fourty-eight years old, it looks to have been untouched as far as the front suspension goes...

In anticipated buying all new stuff, but of late, I have been putting alot more thought into this, in the hopes that I end up buying the right parts, rather than buying something that's perceived to be a good deal (probably because it's local) and being unhappy with the results.

[poncho-mike]

I work for Eaton in the Electrical Power Division. I'm on medical disability right now due to hip replacement and can't log into my work computer. After I go back to work in mid-August, I should be able to get you the specs on any Eaton springs.

Mike