Coil Spring Recommendatoin
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
Coil Spring Recommendatoin
I need to replace the sagging springs on my newly acquired '75. It has a transplanted 427 (w/o air conditioning) and the original springs are sagging pretty badly.
I have seen a lot about 460 and 550 rate springs. I am assuming that these are aftermarket. I have also seen original reproductions that seem to have different rates (430 & 475).
I am looking for a compromise ride that is not too harsh, but not too spongy. I like cornering performance, but not if the trade off is feeling every bump on the road.
I will also be replacing the shocks. Are the Delcos ok or should I consider the Bilsteins?
Thanks for your guidance.
I have seen a lot about 460 and 550 rate springs. I am assuming that these are aftermarket. I have also seen original reproductions that seem to have different rates (430 & 475).
I am looking for a compromise ride that is not too harsh, but not too spongy. I like cornering performance, but not if the trade off is feeling every bump on the road.
I will also be replacing the shocks. Are the Delcos ok or should I consider the Bilsteins?
Thanks for your guidance.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
I have an '80 that originally had the F-41 Gymkhana suspension option that included the 550 lb front springs. I replaced the originals 4 years ago with 550 lb springs from VB&P.
http://www.vbandp.com/detail.aspx?ID=357
I switched to a front mono spring 2 years ago because I wanted to lower my car and didn't want to cut the coil springs.
Handling with the 550 lb springs was very good and ride wasn't bad either. I think you definitely need 550 lb springs with your 427. (I have a GM 350 HO crate.)
I still have the VB&P 550 lb springs: $25 + shipping. PM me if you're interested.
http://www.vbandp.com/detail.aspx?ID=357
I switched to a front mono spring 2 years ago because I wanted to lower my car and didn't want to cut the coil springs.
Handling with the 550 lb springs was very good and ride wasn't bad either. I think you definitely need 550 lb springs with your 427. (I have a GM 350 HO crate.)
I still have the VB&P 550 lb springs: $25 + shipping. PM me if you're interested.
Melting Slicks
Joined: Apr 2006
Posts: 2,202
Likes: 64
From: Bocabec, New Brunswick
My '78 had the F-41 Gymkhana suspension as well. After sitting and sagging for almost 15 years I replaced front and rear suspension with the "Performance Suspension Kit" from Corvette America. The kit came with 550 lb. front coils, 355 lb. composite monospring, 1.125" front anti-sway bar, .75" rear anti-sway bar and Bilstein shocks.
I'm very happy with how this setup performs.
I'm very happy with how this setup performs.
Pro
Joined: Dec 2005
Posts: 709
Likes: 1
From: Lakewood Colorado
Just did this on my 75 with a big block in it. I got the 550's and dont regret it. It is stiffer, but less slop, roll, and bounce. I put a 7 leaf spring in the back as well.
I like it much better. The 550's I put in kept the frame height about the same as it was with stock springs too.
Good luck.
I like it much better. The 550's I put in kept the frame height about the same as it was with stock springs too.
Good luck.
Tech Contributor
Joined: Jun 2004
Posts: 20,804
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I've installed the 460's and the 550's. The 460's were an improvement fromthe original 280's (?), but still not firm enough for me. The 550's keep the front spoiler from rubbing the track when braking hard, and the ride is still very acceptable.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The 550# is a good front spring rate with the BB. Bonus is that you should end up with your front ride height down nearer Power Book road race prep recommendations. I'd suggest you also consider stepping up that rear spring to maintain / improve balance, and get the 8" rear spring bolts so you can lower the rear, as well.
While you're at in, you might as well optimize your geometry. Here's a link with ride height info you should find informative...
http://www.corvettefaq.com/c3/ChevyPower.pdf
While you're at in, you might as well optimize your geometry. Here's a link with ride height info you should find informative...
http://www.corvettefaq.com/c3/ChevyPower.pdf
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
If you're a perfectionist and like to tinker, Koni double-adjustables are the only way to fly.
Otherwise, select the Bilsteins that most suit your needs.
All the others are just that, others...
Otherwise, select the Bilsteins that most suit your needs.
All the others are just that, others...
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Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
It sounds like from his original request that these shocks might be something to look at.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Edelbrock offers a fine product line (love their heads and intakes!), but I'm going with my experiences on this call. I and many others have had a long run of excellent results from Koni and Bilstein dampers, so I believe I'm correct in stating that they are the benchmarks by which all others must measure up against for this application. Why not start at the top?
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
Edelbrock offers a fine product line (love their heads and intakes!), but I'm going with my experiences on this call. I and many others have had a long run of excellent results from Koni and Bilstein dampers, so I believe I'm correct in stating that they are the benchmarks by which all others must measure up against for this application. Why not start at the top?
I had Bilsteins on my previos '70SB. I had Koni's on my 70BB when I bought it. Loved them both. When I changed my front suspension, I wanted that tight feeling but a little softer touch over rough roads. After a little research, I went with the Edlebrock IAS. I really like them and they do give a little better control over bad roads. I don't drive the car too hard, so I can't say how well they would handle under extreme conditions.
BTW, I have the IAS matched up with a 360 rear mono and 550 fronts.
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
I purchased a pair of the 550 springs and got one of them on the car. The other lower control arm was bent, so I am waiting on a replacement.
I put a jack under the new lower control arm and lifted the whole front end off the jack stands. The problem is that the spring only compressed enough to lift the upper arm off the rubber bumber by less than an inch. There appears to be about 3-4 inches of travel from the lower bumper to the frame. I would expect this to be more centered.
Now, I will say that the rear is on jack stands that are about 2-3 feet ahead of the rear wheel centers and this movement of the fulcrum has an impact. However, I did have the whole front end weight on the one side.
Is this normal for the 550 spring? I can't see the ride height yet, as the other side is still disassembled. Won't it continually hit the upper bumber when the load is lightened on bumps?
Any assistance would be appreciated.
I put a jack under the new lower control arm and lifted the whole front end off the jack stands. The problem is that the spring only compressed enough to lift the upper arm off the rubber bumber by less than an inch. There appears to be about 3-4 inches of travel from the lower bumper to the frame. I would expect this to be more centered.
Now, I will say that the rear is on jack stands that are about 2-3 feet ahead of the rear wheel centers and this movement of the fulcrum has an impact. However, I did have the whole front end weight on the one side.
Is this normal for the 550 spring? I can't see the ride height yet, as the other side is still disassembled. Won't it continually hit the upper bumber when the load is lightened on bumps?
Any assistance would be appreciated.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
The ride height with new 550's on my '80 was high but the upper A-arms never hit the bumpers. The jack stands in back probably take enough weight off the front to cause the short travel you're seeing now.
Let us know how things look when you get your car back on 4 wheels. Push it back and forth a bit as the repair manuals say after front suspsension repairs.
Let us know how things look when you get your car back on 4 wheels. Push it back and forth a bit as the repair manuals say after front suspsension repairs.
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
I got it back on four wheels and all worked out well. Ride height is fine and it handled pretty well. Also, I liked the bilsteins that I got.
Looks like I need to replace that stock 9 leaf in the back now to even things out.
Special thanks to MN80Vette
Looks like I need to replace that stock 9 leaf in the back now to even things out.
Special thanks to MN80Vette