[HWYSTR455]

You will drive yourself crazy trying to figure out the 'OE springs'. And even if you do, it will still only be 'stock', not what you want for a suspension with upgraded handling.

Then you have to deal with IF the factory documented changes thru a model year. Like they could change a supplier mid-production, and not 'tell' anyone. Same with replacement parts, which legally have to be made available for 7 years after the cars' production.

A change in production doesn't mean the parts suppliers made a change to their' parts either. And going thru time, they could make changes to make parts that are 'acceptable' for more models, to reduce cost and warehouse space.

Say for example the part manufacturer only made springs in 50lbs increments. So a 289lbs spring could be a 300, or a 250. Then stack the 'accepted' tolerance of 10-15%, for 300, that would be 270 at one end, and 330 at the other end.

Now apply that same scenario/formula to the bushings, and, just to say, there were multiple offering for different durometer specs for bushings. An example would be 2nd gen trans ams, which go different ones than say the camaro.

Now again, apply that scenario/formula to shocks. Might as well also apply that to tires too, going from bias ply to radial.

If by some miracle, the planets align, and you happen to have the actual spring rate. You end up having to deal with today's accepted tolerance, and whatever 'book' the manufacturer got it from.

Like I said, the spring rate is worthless info, and at some point you have to take a leap of faith/best guess. Even then, chances are maybe 50/50 that you will get the results you are looking for.

You take the exact same car, give it to 2 different people and ask for the opinion of the suspension, one will say 'compliant', the other 'harsh', throw that on the pile too.

My advice:

* Make the suspension as free-articulating as possible
* Select a spring manufacturer that has (or uses) a <5% tolerance spring
* Use double adjustable quality shocks
* Use the same durometer sway bar & end link bushings as the control arms (if possible)

If you're lucky, you might get an acceptable setup first shot. It's hard not to compare it to the suspension you had on before, but it's a good starting point. Once you drive it a number of miles, you may find what you thought was 'perfect' only acceptable, and still have to change it to get the original results you were after.

Don't get 'locked in' on any setup, not only may you find better along the way, but your taste may change too.

EDIT: If a spring manufacturer says 'We make to exact OE specs' you immediately know they are full of crap.


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