Rear spring changes

[Antz81]

I Am planning to change my rear spring out for a Composite spring. I've noticed most people seem to go for the 330lb spring for the small blocks (it is what VB&P recommend) but I'm wondering if anyone has tried the 360lb spring in a small block and what they thought of it.
I will be installing bilstein sport shocks and a 3/4" rear sway bay at the same time also.

 

[toobroketoretire]

I Am planning to change my rear spring out for a Composite spring. I've noticed most people seem to go for the 330lb spring for the small blocks (it is what VB&P recommend) but I'm wondering if anyone has tried the 360lb spring in a small block and what they thought of it.
I will be installing bilstein sport shocks and a 3/4" rear sway bay at the same time also.

If your C3 is a daily driver and is never track raced I would use the softest spring available. Do you presently have the 9-leaf spring? If so the softer spring would give a softer ride. And combined with a 20 psi tire pressure it would ride like a Cadillac.

 

[Tom Bryant]

You must be planning on some spirited driving since you are upgrading the shocks and rear sway bar too. I really can't tell you if the 360 spring would be better than the 330. For some reason I can't find the rating for the stock composite so I don't know how the 330 compares. I know mine is not overly harsh but it isn't silky smooth either. It could be I'm just getting old and I don't push it overly hard in the twisties.

I had a '65 small block convertible once that the end link broke on the rear spring and the resulting contact with the road ruined the spring main leaf. A friend had a 7 leaf F41 spring out of a '66 427 car that he was parting out so I jumped on it for $10. It road pretty rough but it sure improved the handling and cornering. It sat a little lower too. It sat nearly level so I never bothered to lower the front to match. I switched from bias ply to radials shortly after and it was a lot of fun to drive.

I guess it's up to you and what you can live with in ride quality vs. performance. Are you going to upgrade the front later to compliment the rear for a complete package?

Tom

 

[navy2kcoupe]

combined with a 20 psi tire pressure it would ride like a Cadillac.

Yeah, and chew up tires like a Winston Cup car!

 

[Antz81]

You must be planning on some spirited driving since you are upgrading the shocks and rear sway bar too.

I guess it's up to you and what you can live with in ride quality vs. performance. Are you going to upgrade the front later to compliment the rear for a complete package?

Tom

Thanks Tom.
I am young (28) so things can get a bit spirited at times. Plus in nz corners are common especially when you know where to look. I'm most likely going to order new front springs at the same time (440lb i think they are) to take advantage of shipping. (If im paying for space in a container i may as well use it) front shocks were replaced last year since I found bubba had fitted the wrong ones and cut the mounts on the shocks to make the work.

 

[Tom Bryant]

It should be a fun car to drive. What do they say about the ride height with these springs?

Tom

 

[Antz81]

It should be a fun car to drive. What do they say about the ride height with these springs?

Tom

Ride height should remain unchanged or restored to the correct height. (stock)

 

[Antz81]

If your C3 is a daily driver and is never track raced I would use the softest spring available. Do you presently have the 9-leaf spring? If so the softer spring would give a softer ride. And combined with a 20 psi tire pressure it would ride like a Cadillac.

It's not my daily but it could see the odd day at the track. Yes it has the 9-leaf spring. Of course the softer spring would give a softer ride. And no thank you, I'll continue to inflate my tires to the correct pressure.

But seriously, who buys a Corvette and wants it to ride like a Cadillac?

 

[Antz81]

I've made up my mind and placed my order. Iv'e decided to go with the softer 330lb spring (the 9-leaf was only 190lb). It is what VB&P recommend for a small block C3 and what they recommend to go with the 460lb front coil springs.

Just need to wait for it all to arrive now. Which could take some time. Since it first needs to make it's way to the shipping centre in CA, and then once all of my purchases are there then they'll come to NZ by ship.

I'll let you know what I think when things get here and are installed.

 

[SVO]

I have the Vette Brakes 360 lb spring on my 72 LT-1 car. Front springs are 550 lb. Shocks are Koni's (wife thinks it has telephone poles for shocks). It rides a bit rough, you do feel the bumps in the road. But it is fun to take the AC belt off and let it rip. I attempted to run a 5/8" ( I think) big block rear sway bar, but for some reason, it caused the car to oversteer badly. You may find the rear bar not really being needed. You will like the rear spring over the original 9 leaf.

 

[Antz81]

I have the Vette Brakes 360 lb spring on my 72 LT-1 car. Front springs are 550 lb. Shocks are Koni's (wife thinks it has telephone poles for shocks). It rides a bit rough, you do feel the bumps in the road. But it is fun to take the AC belt off and let it rip. I attempted to run a 5/8" ( I think) big block rear sway bar, but for some reason, it caused the car to oversteer badly. You may find the rear bar not really being needed. You will like the rear spring over the original 9 leaf.

I do wonder if that's the combination I should have gone for but it's too late now. Either way I'm getting an improvement over what I currently have. If I really think I should have gone with the stiffer springs after I can always do it again in a couple of years, But I don't think that will happen. I picked the 3/4' rear sway bar by looking at the sway bar sets they sell and found that's what they pair with a 1-1/8" front bar, so should work well together.

Basically I'll end up with this kit(C2-C3 Suspension Kits : Grand Touring Plus Suspension Kit, 1980-82) but without the strut rods.

 

[toobroketoretire]

Daily Drivers

As my three C3's are daily drivers and never see track use I prefer the softest ride possible. When I bought my '82 back in 1988 I quickly noticed how harsh it's ride was. I only got a pathetic 25,000 miles out of it's tires and noticed their centers were worn flat when the outer edges still had about 3/8" of tread left. That's when I began experimenting with different pressures and found a low 20 psi gave over double the mileage and a nice soft ride. That was back in the late 80's and I have been running 20 psi ever since. As far as springs go I woulds always use the softest spring available for the superior ride quality it provides.

 

[Antz81]

It's taken some time, but everything is now here. We have a 3 day weekend this week and next week, so should be able to get at least some of it on and tested. If I get time I might get my tires on during the week.

 

[Antz81]

It's all on. I did things one at a time and went for a short drive so I could feel the changes each thing made (except for the rear spring and rear shocks). Felt better with every item I put on. the rear sway bar will be staying on. I still have to take it in to get the new tires fitted, and the alignment checked (I suspect the left front caster is off as I could see marks on the frame where the tire and be rubbing under full lock when making right hand turns.) New tires also feel alot softer than the old ones, It will be interesting to feel the difference they make once they are on.

Is there any point in keeping the old springs? Or just sell them as scrap metal?

 

[73shark]

My experience w/ a 1.125" front bar and 5/8" rear bar made the car close to neutral w/ a slight tendency for oversteer which worked well for me for autoX.