First thanks for all the help upfront. I recently got my 76 and have a direction in mind but want some input from you all. My plans are keeping the appearance stock but I do want to upgrade the engine and trans to near the 300/325 HP area so I have a solid car I can drive regularly. But first I do not like the floating feeling with some steering wheel play and just a slight vibration. So I want to redo the suspension/steering first to get a solid foundation. Any thoughts on full suspension that is reasonably priced and ideas on the steering replacement.

 

Unless you have a actually determined you have worn suspension components, why not start with wheel balance and steering box adjustment?

 

Steering box adjustment might help but I still want to start with a new suspension package

 

May as well tear into it!! See what it needs first. Jack up ea a arm start looking for movement, stuff thats got slop make a plan and get to it!! Great feeliing driving an old car thats tight or better than new, the "Old clunker" facter disappears.

 

Pretty much my thought. These are very nice handling cars when there not worn out. I drive mine with one finger on the wheel at 70 MPH. Front suspension is totally stock, rear has a replacement glass spring. Factory gymkhana suspension. Replacement bilstien shocks. The factory ones got old.
point is. Repair whats worn and or tired. You'll have a nice driver. The more you go away from standard. The harder it'll be to repair again 15 or 20 years from now.

 

So stick with what I got and just replace as needed, I like that much cheaper as well (knock on wood). I want to stay as original as possible long term. Any thoughts on a engine rebuild I want to keep the original engine but want just alittle more.

 

The first two things to check on the front suspension are the rag-joint that connects the steering shaft to the steering box and the idler arm that supports the steering lineage on the passenger side of the frame. Have someone gently move the steering wheel back and forth 6 - 10 inches as you keep your eye on them. They should transmit movement smoothly to the rest of the suspension without any play.

These two items are common wear items that directly impact steering feel and the cars ability to track smoothly down the road. They are also easy/quick items to replace.

Post a few pictures of each when you can, especially the rag joint.

Good luck, GUSTO

 

Ah its a slippery slope. I started by rebuilding the entire suspension with poly bushings. The poly works and its a bit of an improvement, but I wouldn't do it again. They squeak. And don't believe the suppliers who tell you THEIR bushings don't squeak. Rubber bushings are fine. Then I installed a full suspension upgrade kit with stiffer springs, sway bars front and rear, KYB gas shocks, and heavy duty adjustable strut rods. Huge improvement!!! I got my kit from Vette Brakes and Products who are now out of business. Darn shame. Its a great kit, and they were great people to deal with. However, there are kits available from other suppliers. Then I added a Steeroids rack and pinion steering setup. Even after replacing my rag joint and rebuilding and adjusting the box, the steering was still, well, like something from the '60s. The R&P setup is another huge improvement. Finally I installed the Shark Bite spreader bar/upper control arm brace. Bang-for-the-buck-wise, that spreader bar is the best improvement you can make on the C3 suspension. Somewhere in there I also installed the 255/60R-15 tires. Also a substantial improvement. 16, 17, or 18" wheels and tires would provide a further improvement in handling, but I don't care for them. I prefer the period-correct look. At this point I think any further improvement will come from playing with my alignment settings, but its a pain to keep running to the alignment shop for adjustments, and I don't have room for a alignment rack.

 

There is nothing inherently wrong with the C3 suspension design other than possibly could use more positive caster in the front. If your car wanders and is floaty then you have a worn out suspension bushings and worn out shocks. Start by getting those replaced.

For "reasonably priced" upgrades look at good shocks (Bilstein HD or KYB), front upper control arms that offer more positive caster, and marginally larger [anti] swaybars. For improved steering ratio the Borgeson 12.5:1 box upgrade is nice.

 

Originally Posted by jb78L-82 View Post
From another post on suspension and Wheels that I posted a while back:

I have a 78 L-82 4 speed car with the gymkhana sport suspension (67,000 miles) that I have owned for 34 years and I have tinkered with the suspension one part at a time over all those years to achieve the perfect balance of superb handling, steering response and a firm but not harsh ride. Not knowing if you have a base suspension (most likely since most did not have the sport suspension from the factory) or the sport suspension, below is what you need for truly sportscar handling with a great ride for your 78:

Front:

550 lbs front coil springs/1 inch lower than stock-$100
1 1/8 inch solid front sway bar (OEM Bar size)-$200
poly upper and lower control arm bushings-$50
Bilstein HD shocks-$150
Front Spreader Bar-$100
Custom blueprinted/rebuilt OEM steering box- GTR 1999-Gary Ramadei-$300
This modification will make your OEM box about as good as it gets with the OEM steering and very close to a borgeson.....not quite but close
Rear:

360 monospring-$300
Bilstein Sport shocks-$150
OEM Style Rear Sway bar (not the aftermarket type bars. I highly discourage NON OEM/GM style rear sway bars)-7/16 or 9/16 or 3/4 inch (I have this one replacing the stock 7/16 inch bar)-$200
Competition adjustable strut rods with heim joint ends-$200

Total Cost $1750

This suspension will get you a FAR SUPERIOR suspension than what came on the car when it was new, X3 if the car had a base suspension from the factory. You will need to add 17/18 inch rims and tires (ZR rated only W/Y sub rating) later to maximize the superior suspension setup. I have ultra high performance summer only tires Front-255/45/17 ZR and rears 255/50/17 ZR's.



This is ^^^the basic C3 suspension design pretty much unmodified from its original design but maximized for handling, steering, response and grip....I will say this again, the ride is far superior to the OEM gymkhana suspension that came on the car with 255/60/15 crap tires and is very compliant. A neighbor who has lexus LsS460/430 sedans recently rode in my 78 and he commented more than once about the power is great BUT he could not believe how well and tight the ride was....kept saying it.

BTW-the SLP rims and tires above weigh LESS than the OEM aluminum 15 inch rims and 255/60/15 tires..I weighted them both.......................just saying

I said this way back in the beginning of this thread...This ^^^^ will get you a fantastic ride, superb handling, all with basically a stock designed suspension with 17 inch ultra high performance summer only tires.............

I will also add that Karol on this forum with his base stock suspension,L-82 4 speed, and 15 inch aluminum OEM rims with 255/60/15 Radial T/A's, just this past weekend rode in my 78 ^^^^ and then in a back to back comparison we rode in his 78 unmodified base suspension L-82 and he could not believe how much BETTER my car rode than his car (not to mention handle). He loved the rebuilt/upgraded 355 L-82 but raved about the ride....This example is an immediate comparison of real world results, no theory here, with a direct comparison of the 2 suspension types...Not sure what else to say here about this subject.

 

Couldn't agree more with above post. Get the factory gear set-up correctly. And you will have a great car to drive. Interestingly, the above list is near identical to what I have in my car. Poly bushings in front A arms. Rubber in rear trailing arms. 3/4 rear sway bar. (Factory was 7/16th's).
the only thing really different is I don't have Gary's rebuilt steering box. I wonder how much it would cost to ship it both ways from Australia?

 

Man that is perfect thanks for the help that one post answered a lot of my questions. I like the steering box idea. I have a vibration I am trying to figure out. I just got it a couple weeks ago and its not bad and you feel it more in the seat. But I have a lot of playing in the steering wheel and it floats. I do have another question it seems like I do not have a leaf spring at all in the rear it is totally solid. why is that or am I looking at the wrong thing.

 

Here is a picture of the steering box. The play in the steering wheel and the floating feeling is one concern. The vibration might be a totally different thing. You feel it in the wheel and the seat could it be the drive shaft. I was also trying to figure out the whole gymkhana thing and my rear spring or what ever it is is one piece? Am I looking at the wrong thing in the rear.

 

Mike, what you're looking at is one of the aftermarket fiberglass springs that have been available for these cars for about 30+ years. Many folks like them as well or better than the original metal leaf springs that came on your car originally. The spring should have a tag on it somewhere (typically visible from the underside) that tells you who made it and possibly what strength it is. Post a picture of the end of the spring (where it bolts to the trailing arm) if you can't get a good rear view of the entire spring and someone may be able to identify its origin for you.

Your rag-joint looks as good as you might expect an original to look. It doesn't appear to be broken, but the only way to really tell its condition is to do the steering wheel test. Watch the relationship of the steering shaft and the steering-box shaft while the wheel is being moved back and forth. They should move as one, or at least 95% as one. When they need replacing they are either visibly broken or there is more than a few degrees of lost movement between the two shafts.

Good luck... GUSTO

 

I did notice when turning left to right the tires kind of shake or jumpy if that makes sense while parked

 

I’d start with a good alignment and wheel balance. Drive it while it’s right then decide if you need more

 

First thing to do after doing the gearbox maintenance and alignment with a wheel balance is cut a coil out of the front......your car sits nose high......it is going to handle like a car that sits nose high.
Once you get the front end down a bit....add a good pair of shocks (KYB or Bilstein) and urethane sway bar links......then add some nice 17 or 18 rims as stated above......it will be night and day. Next would be the adjustable lower links on the rear.....
There is a lot you can do from there but these mods are cheap and effective.
As far as a suspension "kit"........I think they are a waste of money...and if you do get a kit, stay with rubber bushings, just freshen it up..........if you want to really update what is there, coil over shocks, a multi-link rear changeover, tube control arms.....etc.....etc........
The original Corvette design is a damn good one.....not a lot needed to make a corner carver.

Jebby