Would like to get your opinions on these after lots of reading.

Would like a firm street car that will see an autocross once or twice a year.

Currently seems like a stock front and rear VBP 330 spring and the car handles like crap with the AC Delco Shocks LOL.

I've ordered Bilstein SP for the rear to address the bouncing. Then plan on replacing the spring Rubber Cushions with Poly Cushions.
Smart Struts with Helm joints?? What I can't find is the anti camber kit to eliminate the eccentric setup.

For the front replace the upper A arm with a SPC adjustable, Rebuild the lower with Poly. Replace the spring with a Van Steel 550 and Bilstein SP or Do a Semi Coil over for a little more.

Anything else I should do when I have it all apart?

 

Engine: 383 SBC gen 1 (original block)

Custom Cold Air Intake with ram air design by D&C designs
with moroso intake and K&N filter
Barry Grant Mighty Annular Demon 750 Carbarator
Edelbrock RPM intake manafold
Dynomax tuned ceramic headers
Custom 2 ¾” duel exhaust with X-pipe by D&C designs
Borla mufflers
Fluid damper harmonic balancer
Forged bottom end skat crank
10.5:1 hyper pistons
chromoly rings
Edelbrock signature series RPM roller cam
Comp-Cams hydraulic roller lifters
Comp-Cams 1.52 magnum roller rockers
Comp-cams Beehive springs
Comp-Cams push rods
World Products Sportsman II heads
Heads and intake manifold were sent to Valley heads in So-Cal for race porting, polishing, and port-matching
HEI MSD ignition
March under drive aluminum pulleys
Canton Racing oil pan

Dewitts 3” HD radiator
2 Spall fans
Spal PWM

Richmond Ring and Pinion
Eaton Carrier With Carbon Fiber clutches

TKO 600 Transmission
Centerforce duel friction clutch
21 lb light weight steel billet flywheel
all drive and half shafts balanced

Custom made true 2 piece 18X10 18X8 Centerline Wheels
Rack and pinion steering
Hawk racing pads
Drilled and slotted rotors
Stainless steel sleeved calipers (soon to be a big brake kit by Wilwood)
Wilwood Master cylinder
Hydroboost
SS flex lines
360lb rear composite rear spring
550lb front springs cut ½ coil
1 1/4” front sway bar
¾” rear sway bar
Poly everything except engine and transmission mounts
Bilstin Sport shocks

 

The VB&P 330 lb/in rear spring is a bunch stiffer than stock. You would need to balance it out by installing the GT springs (460 to 480 lb/in) that are available from various vendors, including your local NAPA store. Or even the 550 lb/in springs. Watch out for cracking of the spring perches and shock towers with these springs.
Then I would install a stiffer shock to control it. I have no experience with them, but a lot of guys like the Bilstein Sports for a high rate spring application.

 

Thanks, I should add this is a 427. Yes I know not a great way to autocross but I don't do them to be competitive, just to have fun.

 

I replaced my stock suspension with the VBP Street & Slalom and have been very pleased. My car is very flat in corners

 

First I don't like fiberglass springs, but we will work with that. It's just I wouldn't be able to help you with shock settings. But the best Bilstein setup for general use is called the Sear Point settings. The AC Delco units are the problem with your current set up. Those springs go in both direction, therefore if anyone is running such, then get shocks please with double adjustment and not single adjust!!!!!!

I see you are viewing the SPC, thus which level street or race? Thus with this infinite adjustable unit and it's benefit, don't put stupid poly in your suspension. The stuff is crap. Thus for a true street setup, go get the global west del um bushing set up. For your application, I would even recommend that set up for the upper. Unless you are going to be changing castor and camber at the track and back, like I do, and if youre not, then the SPC's would be a waste. If the frame is bowed or you are having or needing more adjustment, then yes to something like that or just get the Moog offset shafts and slot them. The things to be cautious on with the Global West stuff is to gusset the a-arms, and pin the bolts. The delrin material is so smooth and free in rotation unlike crap poly and the made for the common man stock rubber.
Also smart struts are just a bunch of hype. Just get a traditional heim, rod set up. Smart my &$#$#$! But they are good enough and will keep you in your planned operating parameters for what you want to do!

 

Going to go all out with a VanSteel coil over system front and rear.Wilwood D8 brakes all four corners.My trialing arms are rusty and the bearings are gone so may as well go with all new offset arms with the coilvers.The front A arms are equipped with delrin bushings and have increased caster for better stability.Nice part about coilovers are the adjustability.VanSteel gives a discount to forum members ,Oh yeah and Fathers day is coming up!!!

 

ddawson,

Before spending any money on fancy parts (which I don't have an issue with), take the time and read the Vette Improvement Program by John Greenwood and the suspension article by Dick Guldstrand http://corvette.wikia.com/wiki/Suspension. These are two good articles that will give you the basics behind how to improve and setup these cars. Both these guys use to race C3's back in the day, so they know something about them .

If you get the "smart struts" put them at their highest setting. That is a good location for street and autocross. The lowest setting gives you almost zero camber change which is good for drag racing. As far as the eccentric eliminators go, I got some from Dr. Gas that were for a Mustang but they are out of business. You could try these, but I can't guarantee they will work http://www.totalcontrolproducts.com/eccentric.html.

Unless your going serious racing, which by your earlier comments your not, the Bilstein's should work just fine for your needs. I wouldn't spend the money on good adjustable ones unless you find that you really need them.

Also, don't forget about the steering in these old cars. Make sure ALL the joints (steering & suspension) are in good shape. If your in doubt, change them for good replacement ones. One bad joint, can ruin the handling of these cars. Also, check the idler arm on the passenger side for signs of wear & looseness. I would go with a heavy duty design with a greese fitting (MOOG, maybe NAPA?) instead of the standard duty ones. I prefer MOOG for most of my steering hardware. Good products at a reasonable price.

 

In addition to some good points already made here, it is worth noting that SB/C3 bar & spring recommendations don't always work for an iron block & head BB/C3, tho I believe the weight penalty is a bit overblown. BTDT, and grateful I didn't write off my shark before Mr. Guldstrand's guidance first put me on a better path to sorting it. At the risk of overstepping, I'll assume the bug will bite you badly and take the perspective that you'll become ever more serious about this stuff...

For any type of serious handling, BB 'vettes tend to need more anti-roll stiffness up front than their SB brethren. On top of that, the soft spring, big bar (SSBB) school of thought would have you run standard springs and to rely on however large of a front bar necessary to provide sufficient anti-roll and to balance your car. Thing is, that not only dictates a massive aftermarket front bar, which will reduce overall front grip and become unsettling during single-wheel upsets, but unlike springs, bars don't do anything about dive (or squat). At a minimum, I suggest 550's as a starting point, and to step up from there if/when you find your desire for higher performance handling isn't yet satisfied. FWIW, before you think even higher spring rates out of the question, bear in mind that our effective front wheel rates are only ~1/2 the spring rate.

The next order of business in this department, once everything else is together (and I do mean everything), is to diagnose your car's balance and to dial that in to your own liking by changing the front bar and/or rear spring to suit. FWIW, I wouldn't go larger than a 1.125" front bar, and personally I'm not a fan of 'glass rear springs, nor any rear spring very much stiffer than a true F41 (305#). IMOE, rear bar is not required to properly sort a BB/C3 chassis. While probing the limits, don't assume how your car handles at only 7 to 8/10ths of it's limits will indicate what it will do at 10/10ths. An oversteering car often feels as if on rails right up until it bites you in the backside.

Do lower your front Z height to as near 1-1.25" (per Chevy Power) as practical, and set rear height to where the inner U's are 1/2" above the outers and relocate the inner camber strut links to 1/2" lower than stock C3 relative to the diff housing (per Greenwood). Raising the diff x-member in the chassis will help you achieve this with a lower overall rear chassis height. In lieu of raising the diff x-member with solid mounts, at a minimum install a 3-pc diff locating kit. But, whatever you do, don't set static heights so as to wind up with the body in negative rake (rear lower than the front). These setup mods will lower CG, lower roll centers, reduce jacking forces (particularly out back), improve the rear camber curve, and minimize adverse rear toe-steer in bump. There are other ways to go about "bumpsteering" your front end, but simply installing a set of bumpsteer blocks is the easiest to make a significant improvement.

Component wise, for now I'd focus on R&R of worn bits with quality new ones more than on buying fancy kit. If you're up for the maintenance, poly will greatly reduce bushing compliance, but I'd urge you to go with heim-jointed camber strut kit w/camber lock plates, and to stick with rubber at the TA's if you don't want to bother with sphericals or Johnny Joints. If performance is or becomes a much higher priority than comfort, you might want to consider delrin CA bushings. In any event, install a front spreader bar.

That said, you should definitely reserve space in your budget for the best shocks you can afford, within practicality. It doesn't have to be a set of 4-way adjustable coil-overs (which IMHO is a complete waste of time and money on a cruiser), but this is the last place where you want to get cheap if handling means anything to you. There are a number of good non-adjustable lines of shocks out there, and I've had Bilstein HD's, SP's, and Koni Special D's myself, but having experienced the advantages of multi-adjustable racing shocks during my formula car days I know anything less than a decent set of conventional double-adjustable shocks greatly limit my ability to fine tune my chassis to it's potential.

Alignment wise, I've always thought that either VBP's or Guldstrand's recommendations that best suit your purposes are as good of a baseline from which to work as any. If you get serious and want to tweak things from there (or any other alignment or geometric settings), get a pyrometer and learn how to take and read tire temps. I'm not big on the massive amounts of caster being touted by aftermarket upper CA manufacturers, and believe 2-3* pos plenty for the high-perf chassis. More than that might improve stability, but lessens nimbleness IMCO. Of course, those fully adjustable upper CA's would allow you to have your way here,while eliminating those pesky shims.

Last, but not least, remember it's all about the tires. Not only are we trying to optimize contact patch management, but no matter what else you do, if you still have crap tires you'll still have crap handling. The largest contact patch of the best rubber available is the ticket. That said, you should be aware that there are differences in construction between makes and models of tires which can affect how a car builds cornering force.

Bottom line: Obviously, there are volumes more to this stuff. But, until you understand and do the very basics, and establish where that puts you relative to where you want to be, you'll never get the most from throwing a catalog's worth of high dollar kit and gizmos at your car anyway. Most of us run out of money well before we run out of things we'd like to improve, so take care to do things that should tend to yield the biggest bang for the buck first. My $.02, PayPal accepted.


TSW

 

TSW Mentioned it, but wheels and tires are HUGE in making a C3 feel more like a sports car and not an SUV. Unless you are going to run a "race" tire like an Avon, get rid of the 15" wheels and move up to 17 or 18 so you can get a modern performance tire on there. I get a good chuckle when people dump all kinds of money into their suspension so that it handles "like its on rails" with 15" BFG Radial T/A's

 

Thanks to ( The Skunk Works ) Mr. Charlie, I have really Appreciated your Knowledge on Suspensions of the C-3. I remember when I first started trying to correct mime. Just wanted you to know how much you & other Forum members have helped all of our Corvette Forum members, I'm sure they Appreciate as much as I do. With Regard, Gene

 

Raising the diff and or crossmember is kind of an advanced step to get ultimate handling. First your body mounts better be solids, and you may get driveshaft hitting on the tunnel if you put a passenger in the car. Also for a street car, I wouldn't put a solid front diff mount, your tail bone will appreciate this suggestion. But the aluminum disks on the crossmember for safety--yes!

The trailing arm to frame, the rubber is fine there (I agree), unless you are going full race. Also their are design problems with what everyone is selling. The Guldstrand units are difficult to install and you can't keep them greased. The spherical bearings are trick but hard to install and welding to capture them is how most are doing it. Thus when you need to change the bearing, not fun. And don't get me started on the toe adjusters. Basically the lessor suspension guys don't even have an offering for this attachment point (Vette Brakes, Van Steel). Thus they sell poly to fill the hole. Thus the rubber here is fine!

A big block really can benefit from a spreader bar, but you would have to engineer that in on a big block. Fitting one on a big block car is more difficult than a small block. Thus some guys actually cross brace the frame at points below where a spreader bar mounts.

This is when I was running solid uppers, how I had my spreader bar engineered, before switching to the SPC's



I also have my race car rear spring solidly connected to the suspension trailing arm on my C3

But prior to that, I had made my own delrin donuts.

I also made my own pillow blocks for the sway bars with aluminum block. I also can flip them to run a different size bar.

This is my prior sway bar set up where for street I ran it with the soft bushings, and for the autocross race, I stiffened it up in the aluminum pillow blocks by changing the position to the upper hole. BOY THAT WAS A CRAPPY PICTURE I TOOK!


Observation if you are running vette brakes springs, I would get the shocks that they suggest. Being that they claim to be suspension experts, I hope that their stuff works with their stuff???????????

Going to Guldstrand, as soon as you mention street it will be suggested to go with a 460lbs or whatever they sell in that range of front spring, instead of the 550. They will also try to sell you the other matching components and then your car will handle no better than anyone else. Thus don't say street, if you talk to them. I love the guy, but he got his butt kicked by Herb Adams a couple of times because the Magazines mentioned ultimate street handling. Thus mind stays in the street perspective and Adams cleaned his clock by putting more suspension on the cars. Thus I will repeat, don't say street!!!!!!! Therefore to get the benefit of a Guldstrand suspension, stay toward the race oriented pieces on the higher end of the scale. With those pieces, he would have beat Adams!!!!

My suspension on my C2 race car, I am running solid bushings on the lower and everythign down there is welded and reinforced, gusseted. The uppers, I am running the SPC race arms. For my street performance oriented C3, I have the Global West units and they are sweet (there is nothing better) in this application range. The setup is actually very sophicated, but could be cheaply done, if you can do it yourself. The only caution is protecting the upper Delrin bushing if you are running headers. I will see if I can get over to my storage garage where I have the 1968 and shoot a picture or two of them. They are very trick, but so are the SPC's on my other car.

 

Especially with what's available now. The max performance summer tires offer grip that is day and night over the typical 15" RWL stuff.

 

I've got to do all this in stages so tires and wheels will be later. I'm not new to suspensions after building a few Mustangs and upgrading my C5 Corvette. I even made my wife's Mini Cooper handle like a dream. My last toy was a 2004 GTO with Pedders, Hotchkis, Harrop and Wilwood parts.

For now I would at least like to enjoy driving the C3.

So for now, I've got the remove the steering gear and send it off for Blue Print and new gears. Get new camber rods and bracket.

The Tailing arms are fresh rebuild and so is the from steering components. I'll check the idle arm though per the Greenwood PDF.

I didn't know Global West made C3 parts. I've used them on a Mustang before.

I'm leaning towards Speed Direct Coil over and rebuilt Upper and Lowers with Poly after pricing out new shocks and Duntov springs.

 

I'm running 550/360 on my 78 and like it very good for a street/occasional fun car. The tires are horrible, though. Almost all of my roll can probably be attributed to tire wrap.

BTW, I finally got the car back. Feels great with the new diff.

 

You need to shrink your screen, because when you hit Chevrolet all of the Muscle cars come up on the pop down menu and the Corvette is clear near the bottom. At a screen of 100%, you will never see the Corvette offerings unless you do a search. For a while he had discontinued his Corvette stuff, because no one was ordering and he had enough business from the Muscle car crowd. They are not real big on advertising.

 

Hi,
Where can I find longer A-arm studs for my 68 Corvette??

Stefan

 

spreader bar brace. one ugly weld shows

[QUOTE=TCracingCA;1584049431]


A big block really can benefit from a spreader bar, but you would have to engineer that in on a big block. Fitting one on a big block car is more difficult than a small block. Thus some guys actually cross brace the frame at points below where a spreader bar mounts.

This is when I was running solid uppers, how I had my spreader bar engineered, before switching to the SPC's




TCracing- wish I had seen your design before I fabricated the spreader bar brackets for my 68 BB. I used angle iron and welded the tabs for the Heim joint attachment point. Yours is much neater. RA

 

[QUOTE=ronarndt;1595510381]
spreader bar brace. one ugly weld shows

Thanks for the compliment!! I thought I had went thru the forums and deleted most all of the pictures of any of my unique mods! I guess I missed this one, as it was on C3! I kind of wasn't wanting the track crowd to see my $hit, till I kicked their a$$es! I haven't over the years hung out on C3, but I think I am the person with the most resurrected posts on C2 (I am retired on there now, and super rarely on C3 now)! I spend time now mostly exclusively on PRC and do searches of my most recent posts as to where I left off over there, or as to what people said after I replied to a topic and then see like an old topic show up in the current is how I see these post resurrections!

I am glad you like my unique engineering! One of many unique ways I have modified my cars! I race Canyons and not smooth part friendly tracks (well I have done that too, spent time on tracks! !). I am an old Mulholland and Turnbull Canyon racer! I have been modifying Corvettes now for over 40 years!

One day, I hope to be done with the current projects, and then you guys can see more of my fancy unique ideas (maybe )!! But actually on the current, I have the same idea, but multiple holes for moving the bar fore or aft ! I have like Clogged Gilmer pulleys with toothed belts and cannot run the flex fan with that set up at higher rpms because of harmonics, so I have plenty of room for the cross brace and not just to the towers only!! For street op, I run a quick release coupler for the flex fan and can put it back on for stop and go driving and can pull it off to remove it fast for maintenance or racing. The brace won't fit with the flex fan, so I have to put the spreader bar back on for the street! !

I also no longer run any shins with the SPC/Pole position arms! Just before changing to those units, I had three suspension setups, instead of shims I had color painted coded machined wedges to give me my castor and cambers that I preferred!

I see I missed deleting in this thread my unique capable of being flipped pillow blocks to change sway bar size fast, and the rear spring bolt config, I used to run!

 

I think my old friend Doug who has forgotten me at Global West could still sell you weld in studs for your upper a-arm cross shafts! I don't like bolts to secure those, and his come pre-drilled for cotter pin castle nuts! The bolts back out under extreme driving, so I recommend elimination of those on your a-arm bushings!