Someone go check their archives, need some front spring specs. As some of the regular contributors to this board know, Corvette offered over-the-counter competition front springs for solid axle cars "way back when" that were both shorter and stronger than the factoy OEM front springs. While they were intended for off-road use, they also lowered the front of a solid axle Corvette about 1 1/2 to 2 inches, so a few savy street racers ran down to their friendly Chevrolet parts counter and ordered a set. And in isolated cases, they were successful in their quest. Rare pieces. Does anyone have the specs that show what the tension strength was on these off road springs. If you have both the stock and OTC off road part specs I would appreciate the info. Thanks, David
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Re: C-1 off road springs
Don't have the specs right now--but these were the heavy-duty 57-58 pieces--you might find specs on those somewhere, because they were production items. -
Re: C-1 off road springs
David-----
I can't find any reference to C1 front coil springs that were offered only as an over-the-counter item. If there was such a part available, it was not in the regular P&A Catalogs, either as a SERVICE-only or "accessory" item. If any "special parts" catalogs existed at that time, I don't have one.
In any event, the springs you described sound suspiciously like the 57-59 HD suspension springs that Mike Ernst mentioned. These springs, GM #3748140, had the following "official" dimensions:
free length----11-1/8" (the actual measured free length of springs often varies a bit from the "official" dimension)
wire diameter----0.636"
These springs have a rating of 1145 pounds. Also, they were originally identified by a painted GRAY stripe on the bottom 4 coils. This stripe may or may not still be present. You may need to inspect carefully for any vestige of it. If it's there, then it confirms that what you have are the above. If it's not there, who knows?In Appreciation of John HinckleyComment
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My limited experience tells me...
... you will find the part number very well marked in the HD coil spring itself.Comment
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Re: My limited experience tells me...
Dennis-----
Now, that would be NICE. I've never seen any part numbers on Corvette springs except for those found printed on the paper tags attached to the spring. However, I've never looked at these, particular, springs. Are the numbers "embossed" on one of the coils?In Appreciation of John HinckleyComment
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Re: My limited experience tells me...
Joe, I do believe, in the case of the C1 OTC HD front coil springs, the PN is very much (embossed) in presense on the spring. My exact experience is that number is what told me that a race car enthusiast exchanged the factory '62 coil springs for the earlier (?) HD 59/60 coils on a car I own. Otherwise, I would have never been able to accurately identify the difference.Comment
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Re: My limited experience tells me...
Dennis-----
I wish that GM had done this on ALL springs (and, a lot of other parts, too). For some reason or another, it seems like GM had no real convention or policy regarding the application of PERMANENT identifying numbers, part numbers or otherwise, on most parts. If the person doing the drawing of the part specified it, it got done; if not, it didn't. Usually, there was no requirement for it, though, and the vast majority of parts have no identifying numbers. For springs, this is the very first time that I've heard of a coil or leaf spring with a permanent identifying number on the part.In Appreciation of John HinckleyComment
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Re: My limited experience tells me...
Joe,
Dennis is correct. Original C1 coil springs did have the part # embossed on the spring. I have had several original sets that were so stamped.
Regards, John McGrawComment
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As usual, Joe's info is correct. In
addition, the std coil is .547-.553 gauge and is 13.45" tall free and has 9.75 coils (HD has 8.75); std deflection rate at the spring is 300#/in (HD
is 550 #/in (in '59 - there is some data that indicates 57/8 was 340 #/in), & std deflection rate at the wheel is 10#/in (HD is 200#/in).
I hope you are not referring to these as "off-road" because so many of the HD cars equipped with them found themselves "off-road" on numerous
trips.Comment
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Mystery solved, somewhat
The depth of knowledge with this group never ceases to amazes me. A little more info: I have an OEM set of these springs, which still have the GM parts stickers with GM Part # 3748140, as Joe stated. My part catalogs show this as 57-59 W/HD BRAKE/SUSP, The retail price in 1983, the last book I have that shows the part, is $46.00 per pair. The part book shows these are solid gray, no dot colors mention. However, these pieces are black; the bottom three twists have dots, from the bottom up the first is white, the next two orange. The 300#/in standard / 550#/in HD, was exactly as I remembered. That info was exactly what I was search for, as no part book I have show std. deflection rates. They are what they are, but this color and dot thing remians a mystery.Comment
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minor (?) detail
Took these springs out in the sunlight, and with the aid of a magnifying glass was unable to find any embossed part numbers. Dennis, I am curious, where did the embossing appear on your springs? As I said earleir, the part number paper tags are here and clearly show the correct number and all the measurement specs are correct for 57/59 HD. Thanks guys. DavidComment
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Re: minor (?) detail
Just painted my 62 springs and installed yesterday. The part number is on the side of the coil at the top of the spring(top is where the coil is flattened off). I am kicking myself because I did not take a picture of the spring before I installed them (1rst spring in took a while, 2nd in about 5 minutes!)
ChrisComment
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Re: minor (?) detail
Hope this helps....my unrestored 58' big brake car has the HD front springs with the thicker diameter coils and 1 1/2- 2 less coils compared to a standard car. They (left and right) have the part # 3748140 stamped on the outside of the top coil.Comment
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