In one of the NCRS magazines. Of course it was part of an add for original shocks.

 

I used Bilstein,, all four are B6 ( or HD )
stock front springs,, rear 330# glass spring.
New rubber bushings,, its perfect 👌!!!
IMHO.... The only way to go 👈🤷

 

What I’m really looking for is a discussion of this concept that the shocks designed for the original 63 to 82 Corvette were designed as rebound only which means 10% as your suspension compresses and damp and 90% on the ride back up. not really looking for recommendations for shocks, but the discussion of what this might mean. I guess you can call this a purely academic exercise.

 

The shock you describe, will 'fight' any suspension.

Have you ever driven anything WITHOUT shocks installed? Do that, and it will answer most of your questions,,

 

I don’t believe that is true.

 

Zip sells a '63-'82 replica factory shock set.
It's a 10/90 oil shock...just like factory...

zip-corvette.com/63-82-std-replica-shock-package.html

 

I have never heard that and it sounds like an old myth to me as it makes no sense. Drag race cars need 90/10 shocks in the front. They take a long time to compress, holding the front in the air. Doing the reverse (10/90) would jack the car downward and ride awful. GM engineers are smarter than that. So I doubt this is true. Someone would have to prove it to me.

Here is a somewhat typical shock graph from a shock dyno.
The area from a piston velocity of 50 to 150 mm/s is the most important regarding handling. And it is the force applied here that is important, not the %
Compression is 150lbs in this range.
Rebound is from 200 lbs to 400 lbs.in this range.
Certainly no where near 90%.
More like 42/58 to 27/73 in % terms.


Here is a Koni graph of a Double-Adjustable showing the effect of the adjustments.
Still no where near 90%.
30/70% is more common.

 

So how do you discount that the original shocks were indeed the 10/90 shocks. This is a fact that you cannot deny.

 

The charts and graphs are impressive. But the truth of the matter is that GM had the 90/10. Shocks installed originally. Explain that. Don’t justify changes.

 

​​​​​​​I can easily deny that, until you post a source. You saying you remember reading something doesn't count.

Perhaps start a new thread, too, so folks aren't immediately hostile to your claim.

 

If you’re going to be stupid, don’t be stupid in print. Join NCRS and read the literature

 

So I have to pay to not be stupid? Post a source.
If spending money makes you smart, buy a set of double adjustable shocks. Let us know what settings work best for you. Better yet, charge us for the info!

 

Read the description below the shocks. I don't think Zip would lie...

zip-corvette.com/63-82-std-replica-shock-package.html

 

Another indication of one of the things that is wrong with our society today. Too many have morphed into name calling rather than courteous dialogue when we have differences of opinion. I don't see it much in C3, but do some in C7 and a lot in C8. In this case we call out a very helpful, long-term member of the forum as being stupid when there is a difference of opinion. Whatever.

Back to the question that is being asked. I can understand why there is some confusion. I did a lot of research in this area when I was restoring the suspension, etc. on our '68 L71 with F41. I looked in my NCRS manual, did online research, and spoke with some long-time C3 people who I trust (but it's also possible they are wrong). I focused on F41 shocks, and for '68s, because that's what we have. I found ample evidence that F41 shocks (maybe non-F41 too - I don't know) were 10% compression, 90% rebound shocks. I verified this with Mike at America's Finest Corvettes (CorvetteUSA). Yes, he rebuilds and sells them, so he has a 'vested interest'. Great guy, and knowledgeable. I bought ours from him and they work great. I'm getting some work done right now and don't have time to take pics out of my NCRS judge guide, but I believe it mentions it too - but I could be incorrect on that.

Don't get me wrong, I'm not an 'NCRS nut' or anything. But when I'm doing a lot of work and spending $, I do it the way it came on this particular C3 if at all possible.

I don't pretend to be a C3 expert. I'm learning a lot from my fellow forum members, research, etc. I hope we can do a good job of being respectful when there is a difference of opinion. I sometimes need a reminder too. It's too easy to anonymously fire off some keyboard dialogue that we would most likely (hopefully) not do the same in person.

For reference, I did a 10 second search and found what shows in the pic below (please see the note at the bottom)


. Maybe I'm drinking the expensive kool-aid, but the shocks I got from Mike are great. Peace, Paul

 

Yeah, cool it azhodge...Corvette Central also sells a factory repo. Their description...

These shocks were referred to as 10/90 shocks because as they compressed when your car went over a bump, they had 10% resistance on the way down & 90% resistance on the way back up so the springs did not send you bouncing up too fast. The suspension was designed with this type of dampening.

So really, if you want the true factory ride this would be the shock you want...

 

I still have not seen a dyno graph for these "supposed to be" 10/90 shocks.

Just "saying" that it is 10/90, does not make it so.

Prove it to me.
"Show me the facts"

There are actually four sets of valving in a shock, so there is no telling what 10/90 means without examing the original data.
Low speed & high speed compression, as well as low speed & high speed rebound.

Percentages are the most common misquoted "numbers" in the world, and are typically useless unless the mentioned parameter is given. As in % of "what"
I have to teach this in chemistry class every day, how to correctly analyze raw data.

I have corrected more techincally inaccurate "advetising copy" than I care to remember, and these were for techical scientific products. My all-time favorite was the "hand-held 146 foot long instrument...." Well at least they only printed 100,000 copies like that! So I could care less what the "Advertising copy" statements are, I am challenging that 10/90 statement because it makes no sense.

I would not be surprised if someone made an error analyzing the raw data many years ago, and that error has been repeated so often over the years, it has now taken on a life of it's own, as "fact" when it obviously is not.

So go ahead, prove me wrong.
I am throwing down the challenge glove.

I would like to see the data, and the NCRS "article" referenced.

 

Very well said.

 

It does get interesting, doesn't it. A point I used to make when teaching quantitative methods in grad school was 'if you torture the numbers enough, they'll confess'.

You make some good points and, as I mentioned in a post above, I'm not certain where the truth really is. But one other important fact I uncovered in my research is that all of these shocks, no matter the age or brand, cause cancer in the state of California.

 

The shocking part is why are these old school, old technology, oil filled shocks going for 700, 800, and even $900 for a set of four. Unless someone seen cheaper ones.

 

Bilsteins are much better riding/handling shocks for a driver. Those are really for the 100% original NCRS crowd. Date coded and all. And they probably are repoped with the original valving, whatever that was.
I would just love to see the NCRS article mentioned and see if it was heavily skewed toward 10% C / 90% R.

Anyone have access to that article?