vetteguy75

My original rear is giving up the ghost...so I'm going with a single composite rear spring. Apparently there are several ones to pick from..from 315lbs to 360lbs. I want my car to sit level....which spring should I get? and what about the length of the bolts?

TheSkunkWorks

The rear spring rate should be selected relative to the combination of front anti-roll bar and front spring rates on your car, not simply for ride height. And, unless you like the 4x4 look, I'd suggest avoiding highly arched springs. You can fine tune rear ride height by adjusting the height of the nut on the spring bolts. 8" ones usually work.

vetteguy75

So, the higher the pounds indicated, the higher the arch? My '75 is all stock when it comes to the front end (spring and anti-roll bar)

sstopczy

Call one of the vendors and explain to the what you want and what your current setup is. This will allow them to recommend a spring that is appropriate for your car. VB&P and VanSteel come to mind.

gcusmano74

If you are happy with your car's ride/handling balance now and don't want to change things, look at Hyperco's EZ ride composite rear spring. The rate is very similar to stock (200 lbs/in or so), and it will improve the ride. Get 8" long link bolts and you will be able to fine tune your ride height.
Swapping over to a 315# or even higher spring will change the understeer/oversteer balance of the car, and require a stiffer shock to control. This may be what you want.
You pays yer money and you makes your cherse!

gjohnson

8" bolts will level/lower aftermarket springs

TheSkunkWorks

No. The rating is how many pounds it takes to compress the spring by 1 inch, regardless of arch. A 300# spring will compress 1 inch for every 300 lbs. of loading. Arch determines the spring's final height when it is compressed by a given load relative to its spring rate. FWIW, when dealing with coils this arch factor would be replaced by free length. HTH

MN80Vette

The 8" bolts weren't quite long enough to level my '80, so I ordered a pair of C4 bolts (10") and cut an inch off of them.

Kid Vette