| Re: coils spring source for 1955 Buick Special
Usually, the "heavy duty" springs are for factory a/c vehicles or those that will carry greater loads. Has nothing to do with ride height, but the gauge (wire diameter) more than anything else. There are many criteria in spring design, including "free length" and "checking height" (or at curb or "ride height") plus the fashion in which the ends are finished -- either a stub end or ground flat, on either or both ends. If you can get into the specs section of a spring book from Moog or Perfect Circle, you can easily see that there is no real correlation between free length and checking height, although matching free length PLUS wire diameter might be two ways to make sure of what you get (plus how the ends are configured).
I know that everybody likes to shop price, but Eaton has the orig blueprints and is supposed to reproduce the exact spring specs for each vehicle--at least that is what is claimed. That could also be reflected in the generally higher prices. I've looked at the ESPO website and they seem to be very reasonably priced on their items.
One thing I've noticed on many cars that have "repro" springs on them is that they generally sit too high. On almost all USA brand car vehicles, the lower level of the rocker panel, if extended, usually intersects with the center of the hubcap/wheel cover on each end of the car . . . regardless of brand, unless the ride height was deliberately lower for various reasons. At least that's the way things were up until the 1990s and the "lower in the front" orientation started happening.
Considering how much effort it takes to change coil springs, it might be best to spend a little more and get what's correct and will work as desired.
On the OEM side of things, there were many spring choices (especially after the "computer selected" springs were announced by GM. In the aftermarket, there are usually fewer choices (i.e., a/c, hd, trailer towing), which makes their springs more generic in application for a particular set of vehicles. They always come in pairs, whereas GM had good enough quality control that they could sell theirs in singles and they'd work as desired when only one spring needed replacement.
Eaton Detroit Spring is also a GMRestoration Parts supplier, for what that's worth. If you can find an old parts book that will give GM/Buick part numbers for the springs that fit your particular vehicle and its equipment, that should nail things down pretty well, I would suspect, when you order springs for the vendor to cross into their respective part numbers.
Just some thoughts,
NTX5467 | 
November 25th, 2006
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