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I would like to upgrade the standard suspension on my 327 '66 Coupe. At the moment, everything is original, and the chassis sits very high. I would like to lower it and improve behavior on the street through suspension upgrade and wider wheels/tires (10" rear, 8" front).
Due to the regulations in my country, I cannot use composite springs. This limits me to the F41 spring, which was originally available back in the days. I read here in the forum, that they are quite harsh, but I really like a "racing like" ride. So, I was thinking about buying the following set-up, maybe you have some experience and some advice.
Rear:
HD F41 7-Leaf Rear Spring (from Duntov Motors)
AC Delco Performance Shocks (from Duntov Motors)
Offset Trailing Arms (from Duntov Motors)
Poly Trailing Arm Bushing Set (from Duntov Motors)
So there are two questions open. Do I need a stronger front sway bar (I have the standard)? And should I go for the 550lbs or 700lbs front springs?
This setup should lower my car quite a bit, right?
Have I missed something I should exchange too?
Thanks for your support in advance!
I just re-read your original post.
Measure your wheel wells from the ground to the center outside edge and post it here for comparison of other original cars or better yet start a new thread about this. It may be that someone has replaced the springs with new, higher ones. Regarding the size tires and wheels you are wanting, you will have to go to larger diameter/lower profile tires to get anywhere close to what you want without flared fenders.
Hey, glad to see someone from my neck of the woods!
My '66 has the F41 suspension. I changed the shocks last year to KYB, and they are an improvement over the original-style AC Delco that I had before, which were a bit tired. I don't find the ride too harsh or "choppy", but it's probably because I don't have anything to compare it with...
About tires, the offer is a bit different on both sides of the Atlantic, and I only have good things to say about Vredestein Sprint Classics. With a stock suspension setup, they fit in 215/70 R15 dimension without rubbing, they have a classic look, and provide really outstanding, modern performance. I have done some seriously spirited driving in mountain passes last year, and these tires did a great job.
Before driving my car, I was expecting, just from the big block C2s' reputation, that every curve on wet pavement would be an opportunity for loss of traction, but I understand now that while this is probably true with period-correct narrow bias-ply tires, there is no way this can happen with good radial tires unless the driver consciously pushes the limits. At least this is my experience...
you might want to do a bit of research before you spend a dime with Duntov motors.
I did actually, on several threads here in the forum (regarding bushings, suspension update etc.). Nevertheless, it's not always that easy to find the best solution out of several other threads, especially with the limitations I have from the licence authorities. Duntov was recommended from some people here in Europe, therefore I mainly checked there, because of the references I had. I hope you don't mind,...
Originally Posted by 68hemi
Originally Posted by Maisbiensuer
Ahh ok, now I understand. I agree.
So, that means I have to stick to the original rear spring. New HQ rubber bushings at the rear is clear. Longer rear spring bolts too. Avon tires too.
Larger anti-roll bar (with poly bushings) at the front is clear too. Which dimension/strength do you suggest? What about the front springs (as I would like to lower the car)?
Just to give you an impression, this is the type of racing done in our region (Corvette at 1:20):
I would not suggest lowering the car, it will limit the size tires you can use which are already limited by the small size of the wheel wells on C2s compared to C3s
I just re-read your original post.
Measure your wheel wells from the ground to the center outside edge and post it here for comparison of other original cars or better yet start a new thread about this. It may be that someone has replaced the springs with new, higher ones. Regarding the size tires and wheels you are wanting, you will have to go to larger diameter/lower profile tires to get anywhere close to what you want without flared fenders.
I will definitely ad wider quarters to the body of my corvette, there is no limitation from that direction. Regarding tire dimension, the outer circumference need to be as close to the original circumference as possible (+/- 8%), that's part of the regulation.
And I will do the measurements for the height reference.
Originally Posted by Jan25
Hey, glad to see someone from my neck of the woods!
My '66 has the F41 suspension. I changed the shocks last year to KYB, and they are an improvement over the original-style AC Delco that I had before, which were a bit tired. I don't find the ride too harsh or "choppy", but it's probably because I don't have anything to compare it with...
About tires, the offer is a bit different on both sides of the Atlantic, and I only have good things to say about Vredestein Sprint Classics. With a stock suspension setup, they fit in 215/70 R15 dimension without rubbing, they have a classic look, and provide really outstanding, modern performance. I have done some seriously spirited driving in mountain passes last year, and these tires did a great job.
Before driving my car, I was expecting, just from the big block C2s' reputation, that every curve on wet pavement would be an opportunity for loss of traction, but I understand now that while this is probably true with period-correct narrow bias-ply tires, there is no way this can happen with good radial tires unless the driver consciously pushes the limits. At least this is my experience...
Ha, what a nice surprise :-)
Hmm, but as you have the big block Corvette, the situation with the F41 suspension is maybe a litte bit diffrent?
I checked also the Vredestein Sprint Classics tires, they are not available in the width I would need it (9 to 10" wheels at the rear).
Last edited by Maisbiensuer; 02-14-2018 at 10:15 AM.
I haven't wrote for some time in this thread. I wanted to first check all the mentioned reference-threads and I have read the book from Fred Puhn "How to make your car handle". So, I guess I'm now better prepared for the discussion.
After all the reading, I'm tending towards this setup:
Rear:
Offset trailing arms
Rubber bushings all the way (from Bairscorvette, I read that they are quite good) Open: Leaf Springs and Shocks (I'm limited to the traditional metal springs, and as the F41-Option seems to be too stiff (I have the 327 engine), I guess I have to use the standard one)
I got they people in this thread which say that I should change one by one piece and should try to get one by one step to the solution which fits for me. But the thing is, that my car is still on the way to Europe and I have now a chance to do a complete shipment of parts. The normal shipping through is quite expensive. Therefore I'm still searching for a already proven set-up on this. Even if it isn't the perfect solution in the end, it's a start in the right direction and it's better than to pay high shipping costs for every change. Even if I now know how to calculate spring rates etc., I still have no possibility to measure things on my car.
So therefore I'm asking, does anybody has a proven setup for an advanced street racer? Maybe with Bilstein shocks?
My opinion is that F41 is great for the street and auto crossing. I switched my 1967 327 convertible to F41, a 3/4" (19.25 mm) front sway bar and Bilstein Heavy Duty shocks about 10 years ago. Prior to that I had tried many combinations to get the car to handle better FOR ME in auto crossing and general pleasure driving. For example, one combination was a 1-1/8" front bar and rear big-block 9/16" bar; that was just too stiff on the street, although a friend loves it on his old Corvette. As is well known, every driver has a preferred suspension set-up; what is perfect for one driver will be just so-so for the next guy.
The F41 is not too stiff at all on the street, even in California where the once-great roads are now pretty bumpy. The photo shows me cornering hard at an autocross, and you can see that the suspension still allows quite a bit of roll.
I'm coming to the hindsight, that I anyhow have to play around with all the possibilities, I guess I will have to order some parts in diffrent executions to have the possibility to play around a bit. It's still cheaper then ordering it one by one with the overseas shipping.
Would you mind to tell me what kind of coil springs you are using on the front?
I'm coming to the hindsight, that I anyhow have to play around with all the possibilities, I guess I will have to order some parts in diffrent executions to have the possibility to play around a bit. It's still cheaper then ordering it one by one with the overseas shipping.
Would you mind to tell me what kind of coil springs you are using on the front?
My rear leaf spring is definitely from Eaton. I thought my front coils were from Eaton too; however, I looked on the Eaton site today and they only have standard front springs, not F41 front springs for my car. So, I'm not sure who I bought the front springs from 10 years ago. Perhaps Eaton formerly sold F41 coils, but now they don't. Sorry I can't be of more help. The NCRS technical discussion board would be a useful place to look for spring information; that's where I would look if I needed to regarding springs.
I have the Eaton 7 leaf as well and 550 front springs from VB&P with Koni Red adjustable shocks. The ride is not harsh or too firm whatsoever. We also have an original F41 on the kids '76 and it got rid of the soft soggy ear end that the 9 leaf provided.
Thank you all for posting in this thread and your support.
I've digged in further into this suspension topic, and also read a lot about QA1 adjustable shocks etc. Still not defined my setup yet :-)
I've checked for more information about Brian Hobaugh's Corvette, which is some kind of a good example for the handling I'm looking for. Brian's Corvette has a 6 leaf spring rear suspension (see Picture). Quite close to the F41 rear springs.
I'm currently leaning towards the 550lbs front springs, F41 rear springs, QA1 adjustable shocks. My thinking behind this, that if I don't like the F41 suspension, I can go back to stock and still using the QA1's.
What I cannot use are the coilover systems, due to licence registrations in my country.
02-13-2018, 06:48 PM
