Stencil on '64 leaf spring

[Ed S.]

Removed the leaf spring from my 64 today. Found two stencils on the large leaf. Does anyone know what they might indicate? Car was restored - body off, about 15 years ago. Don't know if this spring is the original or not, I suspect it is not. BTW - removed spring to get access to the differential, it is coming out for a rebuild. Also - the car's stance, was good with this spring - which surprises me if it is a repro, considering all the horror stories I've heard about after market springs.

The stencil markings are: JSR and 21-307. Both stencils are on the same spring. Now that I think about it, the leafs are painted flat or semi gloss black. I believe originals were not painted. The white stenciling is on top of the black paint. I assume this is a good indicator that the spring set is an aftermarket unit, 9 leafs. But still don't know the purpose of the stencil.

[Ed S.]

Re: Sencil on '64 leaf spring

Found the answer. I did a search for JRS leaf springs. It is John R. Spring Service in Michigan. the 21-307 is the JRS part # for a 9 leaf spring for mid year Corvettes. Ride height is perfect - I think I will keep it.

[Gary B.]

Re: Sencil on '64 leaf spring

Ed,

Can you show a close up image or two (top view; side view) of the end treatment for any leaf other than the main?

Gary

[Ed S.]

Re: Sencil on '64 leaf spring

Gary,

The pictures you asked for are attached. The first pic shows all 9 leafs - birds eye view. Smallest leaf is at the top, notice there is a cluster of 3 springs banded together at the bottom. Second pic is a side view of leafs 4 through 9. Third pic is leafs 1 to 3, # 4 is also partly shown at the bottom. Pic # 4 is just the ends of leafs 4 through 9.

I am pretty sure this is an aftermarket spring set from John R. Spring Service - thus the stenciled JRS on the main spring. Obviously this spring set is not even close in appearance to an OEM spring or a good repro of OEMs that are available from some vendors. But, that said, I can tell you that when this spring was installed the ride height was dead on, I did not have to have long 10 bolts and the ride was good, firm but smooth. I have since identified a source for an original standard suspension C2 spring set that I intend to refurbish and install in place of the JRS spring I removed.

If nothing else the photo set you asked for (and I attached) provides a good reference of what a repro spring looks like.

[Gary B.]

Re: Sencil on '64 leaf spring

Ed,

Thanks for the photos. The stenciled number is the number assigned to that spring by the Spring Research Institute. In terms of geometry your spring will likely garner some sort of deduct during judging. The ends of the main leaf should be cut at a 45-degree angle and not the angle on your repro example. Also, original C2 and C3 springs had what were called tapered rolled ends, which again your springs does not have. If you ever wish to replace your spring, currently the best repro in terms of the cosmetics is made and sold by America's Finest Corvette, although be prepared for sticker shock. If you're interested in learning more about C2/C3 rear springs, there are several articles in the Corvette Restorer over the past ten years that described original and repro springs.

But if your spring has the correct ride height and you're not worried about a few judging points, then there's no reason to change it assuming it's not weakened and rusted from long exposure to salted roads.

Gary

[Ed S.]

Re: Sencil on '64 leaf spring

Gary,
Thanks for the diagnosis. I looked at teh American's Finest website, they do not list a 9 leaf spring for mid-years, only several versions of a 7 leaf unit. I've e mailed them with a request for 9 leaf info but haven't heard from them yet. I intend to follow up on the OEM spring I have learned about - excellent price, worth investigating. Thanks again.

[Gary B.]

Re: Sencil on '64 leaf spring

Ed,

AFC sells a repro 9-leaf, but they don't advertise it.

Gary