augiedoggy

So I bought a set of viking dual adjustable coilovers for the front of my c3 from CPP a couple years ago when they were running a special. I have the rear shocks on the car already with an unknown but suspected 340 VB&P rear composite spring I bought used.
Anyway the included springs for the coilovers are only a spring rate of 350
One of the few things I miss about my old 84 Z51 handling package vette was the great cornering capability. Based on that and the reading ive been doing on old threads it has me wondering if I would be better off with 500-550lb front springs and upgrade to the 1 1/8" sway bar?
I have the POL tubular a arms and offset mounting shafts as well to install this spring along with a borgeson setup.

I DO plan on dropping the front of the car about an inch and I have the vansteel delrin bushings that raise the rear diff about 3/8" up into the car allowing me to lower the rear a bit. The car is a 74 with a SB with alumium heads, intake and radiator. I do not plan on racing our autocrossing the car but it does see spirited country road driving.

So my question is am I right to think something along the lines of a 500-550lb spring in the front would suite me better? I mean with the dual adjustable shocks I can still dial in the ride quality a bit. I'm thinking the stiffer spring will work better with the lowered suspension and 18" rims with wider corner tires.

augiedoggy

Well I picked up a set of 500lb springs. The pile of stuf ive bought and wont be using just gets bigger..

gkull

A good thing is to buy the adjustable spring end links for 1 1/8th sway bars.

255 width front tires of the AA A rating have the best traction.

500 is a good starting point

Dual adjustable have so many different settings, but try 10 and 10 to start. It really depends on how much you brake and general road surface

Bikespace

I ended up buying a QA-1 swaybar on sale. It's 1 1/4" OD, but hollow. Assuming the rest of the dimensions are the same, and the steel is the same, it should be about 15-20% stiffer than the stock 1 1/8" bar that's in my 80, while also saving some weight (No exact numbers until I can find that spreadsheet).

https://www.speedwaymotors.com/QA1-5...ch,455963.html

This, and some QA-1 semi coilovers with 500 lb springs, are awaiting install in my 79.

The endlinks are not adjustable, though. @gkull, do you have a link for those? And/or an opinion on the even stiffer front swaybar?

gkull

https://www.mamotorworks.com/corvett...ane-kit-602596

leigh1322

I would recommend the ~550# springs and the factory late model C3 gymkhana 1-1/8" sway bar.
The stock C3 SB parts are pretty soft.
That will probably give you the greatly increased responsive handling you want.
It will be pretty firm. But you should be able to tune it in to ride nice with the double adjustable shocks.
About 60% of your roll rate would be the sway bar.
The bar does most of the cornering work and a little thickness change has a huge effect on the rate.
The larger 1-1/4" sway bar pushes that a little too far, unless you are racing.
The car will only roll 1/2" in a 1G corner. You really do not want any less.
On full G cornering and throttle you might get to a 1" drop in the outside rear. Or same on trail braking.
It's a good place to be. A stock C3 rolls around twice as much.

Spring rate at the wheel:
250# SB springs = 97#
550# = 214#
7/8" SB Fr Sway bar = 185#
15/16" BB bar = 243#
1" bar = 315#
1-1/8" bar = 504#
1-1/4" bar = 769#

So as you total wheel rate jumps from 282# stock to 718# your shock stiffness needs to double to control it and "feel" the same.

I did all the math for you guys:
See spreadsheet tabs 1,2 & 3

The adjustable end links for the front bar do let you soften the rate and easily adjust the fr/rr handling "balance" of the car.

Bikespace

1 1/4" QA-1 = 584#

Thanks for posting that! That saves me having to find my spreadsheet.

The QA-1 1 1/4 bar is hollow with a 3/16" wall thickness (which isn't accounted for in your spreadsheet). So it's the same effective rate as a solid 1 1/4" bar, minus the rate of the 7/8" bar that could fit inside it. 769-185 = 584#. That's 16% stiffer than the stock (for 80-82) 1 1/8" bar. It should also weigh about 4 lbs less. I'll try to get exact weights of the bars I have sometime.

augiedoggy

I have a new 1 1/8 swaybar and the spring tensioned end links on order...

Thanks.

leigh1322

That should do it. It should lean half as much. You'll probably have a hard time feeling it lean at all unless you take a pic.

cottoneg

I have had the Daytona Suspension and F41 suspension.

I went to the 1 1/8" sway bar. For my driving, it was not a good fit. I felt the car understeered more than I liked.

leigh1322

I had fully adjustable sway bars fr & rr on my road racing 70 Z28.
It was very sensitive to even minor adjustments.
Too bad no one makes anything like that for our cars.

CraigH

I ran 450lb in the front with QA1 double adjustable shock bodies with both stuck a-arms and with Global West tubular arms.

My ride height was fairly low and they did a good job.

Have recently kept the Global West arms but gone from semi to full coilover in front with Ridetech coilover body and 500lb springs.

i think the latest setup has better ride quality and control but he’s things can be subjective.

augiedoggy

I have a lot of upgrades to put in the car and the list just got bigger as I picked up a std bore sbc400 last night for $200... I need to go through it and at least freshen it up with new bearings but the stock dished pistons will work great with my 64cc heads for 10.2:1 compression after I drill some steam holes. Since I dont care about high RPMS much being a cruiser I think the stock cast lower end will do fine with some ARP bolts holding it together but I wont know for sure till I tear it down and check things.

I do also have tubular a arms and an overdrive trans with a 3.55 rear end and the van steel delrin rear support mounts to lower the rear, new rear trailing arms and strut rods along with a borgeson steering setup to also install