[RJP_Gen1]

I know that this question comes up often, but I'm looking for input on the proper shocks for a very stock firebird 400 convertible. I'm looking at the following options and would like to hear about your experiences and recommendations.

Gabriel ultra/classic - a simple stock replacement. How is the ride quality and handling?
KYB excel-g - good enough ride?
KYB gas-a-just - read that these are a bit too harsh.
Bilstein - seems to get great reviews, but I can only find shocks for the front. Can't seem to find shocks for rear w/ mono leaf suspension.

Any suggestions?

[Cammer-6]

you forgot Konis
that were an option

[RJP_Gen1]

Yes, Koni is an option, but are expensive and I'm looking for a nice comfortable ride with decent handling. I'm not looking for any adjustments. But I'll add them to the list. Looking for suggestions on the best option for an improved stock ride.

[694.1]

Those Gabriel Classics are rather "flaccid."

[JLBIII]

I'm running Bilsteins on my 68 coupe along with new Eaton springs. I'm real happy with the ride and handling.

[RJP_Gen1]

Thanks.

Were you able to get Bilsteins for the rear? The catalog does not show any part number for rears.

I've been reading more about the Koni Classic adjustable Reds. These are oil charged shocks (not gas). Anyone have experience with Koni Classics for their first Gen? Again, a stock suspension and only street driving for me

[JLMounce]

The Gabriel shocks have a good ride quality. Of the ones you listed, they will perform most like the factory spiral shock that would be on the car. For a stock type ride and experience, it's the one from your list I would use.

With 100% stock components in the car, outside of the factory type shock, I think I'd run a Koni classic, likely set to near full soft.

[RJP_Gen1]

JLMounce....we think alike. I purchased a set of Gabriel shocks (82040) for the rear, which are sitting on the bench right now. The prior owner installed Monroe OESpectrum's on the front (which are fairly new). However, I've read a lot about hydraulic shocks for 60s cars and think that the Koni Classics would be an excellent (albeit expensive) option.

Option 1: Leave the Monroes in front and install the Gabriel's in the rear (total investment for rear, $60).

Option 2: replace all four shocks with Koni Classics (Red) and set the adjustment to soft. (similar to your suggestion). Investment would be just about $550-$600.

Okay....money matters, but if I don't consider Koni, I may never know whether I'm getting a great ride. On the other hand, if I pay that much for Koni shocks and find that the ride isn't much better than standard OEM type shocks, I may hate that I wasted all that extra money (which could be spent on Rally wheels maybe.

To make matters worse (or better), I need to do the exact same exercise for my 64.5 Mustang Convertible. It too needs shocks (I haven't changed them in 30 years).

Time for some voting....(Monroe Fronts/Gabrielle rear) OR (Replace all four with better shocks such as Koni).

[JLMounce]

If you already have the Gabriel's on a bench, I'd throw them in and see how you like it. Then make a decision from there.

[RJP_Gen1]

I should mention that the Gabriels are new in the box. I can still return them for credit. Once installed, I own them. So the investment in Kona's goes up if I don't like them. Truth is, I'm not sure what I will learn, since I can't really tell how much better it can be until I try both. Ah, the enemy of 'good' is 'better'

[JLMounce]

Even full soft, the Koni Classic is going to provide more damping than a stock suspension firebird needs. The classics also have a digressive damping curve, compared to a progressive damping curve like the factory shocks or the Gabriel shocks.

If you like the somewhat floaty nature of the driving dynamics of a stock suspension firebird, you may not like the Koni Classic. It will seem more taught in normal day to day driving.

Here's a generic graph for visualization purposes. You can see in how the damping ramps how that might "feel" while driving.



The first gen firebird is woefully undersprung and underdamped IMHO but that's a different discussion. If you want the car to behave as it does from the factory, I do think the Gabriel is the better choice.

[RJP_Gen1]

Thanks man, good info and (maybe) you saved me a few bucks

So, many people say 'Monroe and Gabriel are garbage', while far more say how great Koni and Bilstein are. I guess it does depend on the car and suspension.

[RJP_Gen1]

One more question....isn't 'Digressive damping' suppose to be more ideal than 'Progressive damping" for most driving conditions?

In other words, wouldn't Progressive feel a bit mushy at the beginning/middle of the curve and a bit harsher at higher velocities - as compared to digressive? Or, am I reading this incorrectly.

I guess many it's the 'floaty' nature of stock shocks that I'm trying to improve. I like comfort, but not floaty (if that makes sense).

[JLMounce]

You're reading that correctly. A digressive valved shock will tend to have a more taught feeling at low speeds compared to a progressive shock that will float a bit. At high shock velocities the progressive shock will feel more harsh.

Modern cars almost exclusively use digressive valved shocks. They tend to control oscillation, especially with stiffer springs, quicker. So you get that bump then set feel instead of the bump then float feel. If you want to get away from that soft float, going to a digressive valved shock will help with that. As will going to stiffer springs in general.

[rdl]

I recently refreshed my suspension last Summer. I re-clamped the original rear leaf springs, and replaced the front coils with factory spec’d replacements. Then I installed new reproduction spiral shocks all around. The observation I will make is that most people forget that replacing a worn part is always going to feel better on that basis alone. An alignment and fresh polyglas tires all around, has made for an amazing refreshed ride experience. Good luck with your project!

[RJP_Gen1]

Thanks for the input rdl.

I'm curious how you feel about the repro spiral shocks. My car is nearly all original (even down to the carb), so I'm always trying to stay as close to original as possible. Spirals would look correct. However, I read that spirals look like originals, but ride dynamics are not nearly as nice as modern shocks (when comparing the $$ spent for each). Spirals are just about the same cost as Koni and Bilsteins.

How do you like your spirals? Did you do it for concours reasons? My car is original survivor grade, not a concours resto.

Thanks

[rdl]

I bought the shocks for originality, but have not been disappointed by the quality. I drive my car 2K - 4K miles per season, and race it at the strip once per year. It’s an excellent #2 example so originality in look and feel is important for me. That said, none of the typical driving I do (highway or cruising) suffers from OEM grade components. I hardly ever feel lateral G-forces getting ice cream. For what it’s worth, ask yourself what kind of driving do you actually do, rather than what the glossy part brochure says you can do.

[RJP_Gen1]

haha...probably an easy one to answer. I always drive for pleasure and am never driving my 67 400 convertible above 75 on the highway. Most of the time, it's backroads and ice cream.

The big issue (for me) is the terrible New England roads. Nearly every road is littered with pot holes and frost heaves. I'm looking for a more 'sporty' feel, but I do not want a harsh ride while on a pleasure cruise. I don't show the car (well, maybe an occasional cars and coffee).

I'm sure that the basic OEM shock will do its job. But everything I read suggests that Koni classic Reds offer a much better driving experience. These cars were designed around hydraulic shocks, so I just figured that a hydraulic shock would be more appropriate (vs gas).

Again, I don't race....I'm a pleasure cruiser. But it's a firebird 400 after all, and should at least have some ability to be driven more spiritedly in corners without body roll and float.

[JLMounce]

what's your budget for suspension?

For the type of driving you are describing, I'd probably recommend a set of Global West 1" lowered front springs and rear leaf springs. These will typically sit around where a car with a 50 year old set of springs will sit. Not lowered, but not quite factory either. What you're after is the increased spring rate. I'd then add a .5" tall ball joint to the factory upper control arm along with offset cross shafts. For shocks I'd go Koni Classics or Bilstein HD's. Then add a 1 1/4" hollow Helwig front sway bar.

If the front end steering needs rebuilt, or the factory control arms need new bushings, install those as well. The same goes for the steering box's rag joint if needed.

Then give it a modern alignment. -.5* static camber, 3-4* positive caster and 1/16th" toe in.

The car will now have a firmer ride that isn't harsh, turn in much more crisply, track better at higher speeds and hold more grip if you need to throw it into a corner. Except for the outwardly visible difference in the shocks, nobody will really be the wiser.

[RJP_Gen1]

Thanks for the setup advice. I lowered my Mustang by an 1" many years ago, so I can surely do the work. The lower ball joints were recently replaced and the steering is pretty tight (it's a low mileage car), so I was hoping to take this in phases by starting with shocks now and working towards other upgrades later. Maybe that's a solid reason to go for the low cost Gabriels now and work towards the Koni reds when I upgrade other suspension parts later.

Thanks again