[Shiny]

I tried to click an answer and struck out on finding "original" spring specs, although I'm sure they are out there somewhere.

Reading all these posts (and locomotivebreath's earlier thread), I feel it is tricky territory. If I ever decide to change mine, sounds like going to a "custom" supplier will improve chances of a good ending.

Originally Posted by HWYSTR455

Not sure what stock is, but they have a higher free height. The 'performance' springs that most sell are shorter.

Shorter springs are easier to install, can do it without a spring compressor.

I think the OE ones are like 450 or something? You can look it up, but it's pretty worthless because of the design of the system. And they used like 7 or more different types/specs of springs.

They didn't use different springs per side, they always used pairs of the same rate/length.

Once you go to aftermarket control arms or control arm bushings, the control arms articulate much better/easier, and that's why a higher rate is needed.

The control arm bushings have teeth, bite into the frame, and adds resistance. That's why you have to do OE bushings with the car on the ground at ride height. Shocks are different too for the OE suspension.

Once you have a free articulating suspension, and you get the spring rates dialed in, you can tune with shocks & bars.

Spring manufacturers that make quality springs are companies like Landrum and AFCO, but most of the time you need to provide specific specs. People who have been dialing in 64-72 GM A-bodies for a long time know what works.

Pretty sure Global West uses Landrum, but Doug uses his own specs. There might be one or two off the shelf ones he provides, but in general, think he uses his own numbers.

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HWYSTR455 - thanks for the education. Your explanation of bushings and springs makes sense.

A MOOG "partfinder" I found online says their 5372 front and 5401 rear are standard for a 70 LeMans without AC but I don't trust it since they didn't list any options where I was looking.

Here are some specs for these two PNs that someone else claimed are from MOOG catalogs:



So these are not stiff at all - front is 289? lbs/in. This is a lot softer than 500, so the "clamped rubber" stock bushings must add significant stiffness.... at least assuming these Moog springs are anywhere near stock...

Originally Posted by locomotivebreath

Stock drum spindles , these are generic 2” drop springs from Jegs - 500lb rate . Love the look but it needs to come up an inch or run a tire taller than 26 . I’ll drag coming out of the driveway if I don’t cut it right .

locomotivebreath - do your control arms use aftermarket bushings or the stock "clamped rubber" type as HWYSTR455 explains?

Originally Posted by sglemans

Lcmotivebreath, that's kind of what mine looks like now, might even be a bit lower than that. The ride is super-soft though, so I think it's just saggy original springs, not aftermarket ones.

sglemans - as you work through this, please post what you learn and end up doing. If the spring rate I found online is anything close to stock, maybe they would feel "super soft" by original design?

Would obviously be helpful if someone could post all the original spring options for 68-72 Tempest, GTO, handling packages, AC, etc. I found some discussion about this for 64 GTOs here in the forum (linked here) and it sounded quite complicated.

Mike