[JLMounce]

TL : DR - The Global West L2 Cat 5 springs are pretty awesome, but the install is a bit more involved. Likely not recommended to casual drivers due to firmness and cost. The QA1 Pro Coils are likewise pretty great, but again given their expense, likely a waste of money for anyone that is never going to have a need to corner-balance their car. Stick with conventional springs and shocks.

Over the past couple weeks, I took the front and rear springs out of my '69 Bird for some new equipment.

Previously the car sat on Hotchkis 3" drop leaf springs, Hotchkis 2" drop springs and I used Verishock SS shocks.

After my engine upgrade last year, I started noticing some deficiencies in the handling department. Funny how an extra 150hp will do that. Specifically, the rear end was far too lively. It was unloading very abruptly during slight power corners and during heavy braking. The ride was never terrible with this setup, but the rear was always a bit jarring and you could also feel the front end hit travel limiters at times.

I spent a solid month and a half researching just about every avenue for suspension changes. I spoke to anyone who offered a link style suspension upgrade, as well as with Global West regarding their Cat 5 leaf system.

I've never learned to weld, so much of the link style suspension upgrades would have required me to send the car off for work. I haven't been particularly impressed with any work I've had done on the car recently and given the quotes I was receiving, really pushed the idea of a 4 link or torque arm system out to left field.

Add to that the fact that most of the link setups require hacking off the back section of the exhaust, or in the case of a torque arm, removing the cross-over, that was also additional expense on a car that is largely "done."

costs involves, it became pretty easy to go with Global West's solution. A set of custom made L2 leaf springs that come in around 180# and their Cat 5 high misalignment bearing setup. To match the rear and gain some adjustability, QA1 Pro Coils with 600# springs were spec'd. Shocks are QA1 double adjustable all around.

Some of you may rightly point out that I typically don't recommend these hybrid style coil-overs. That is true. I still believe that the side loading imparted on shock body by the conical, uncaptured spring represents a failure point. That said, these shocks have a lifetime warranty, that I made sure to promptly register and they are readily available and can be rebuilt if necessary. That gives me a bit more piece of mind.

There are a couple coil-over shocks on the market that can be adapted to my SPC lower control arms and the factory shock mount. These specifically are the RideTech coil-over and the Verishock coil-over conversion. Both use a stud mount that captures the top of the shock into the factory shock mount. This allows the spring to be captured to prevent side-loading. However the factory shock mount isn't really intended to see those types of loads and the RideTech shock with a T-bar conversion on the bottom would be rigidly mounted and could damage itself, or the shock mount. The Verishock has a swivel ball top that overcomes this, but due to the size of the ball mount, it's highly likely modifications need to be made to the upper mount to accommodate it.

Long story long, the QA1 Pro Coils became the only real way to add adjustability and spring rate with my need to keep from fabricating a whole bunch of stuff, or ditching my current SPC arms. So...I decided I'd give them a try.

As for the installation, the Pro-Coils are easy to install. Arguably easier than installing a factory length conventional coil spring. Since I purchased from GW, they included the thrust bearing kit and multiple spanners which makes ride height adjustment a bit easier.

The leaf springs were more involved. Partially because you have to press in bearing shells to the frame and partially because I use the RideTech subframe connectors which have an integrated front eye pocket. The integrated pocket is deep enough to allow full articulation of the leaf spring's tilt, but the pocket is not designed for a reverse eye leaf. There is an ear on the outboard side of each pocket that interferes with both the vertical and twisting motion of the spring. Fortunately removing these ears doesn't get into any of the structural pieces of the connectors, so a couple cuts with the cut-off wheel gave me the clearance I needed.

Wrestling the rear end into position on the leaf springs is made more difficult by the fact that they do twist. You're in a bit of a fight to get things seated properly as when you move one side, the other side isn't necessarily locked in place until the lower shock plates have captured the leaf pack to the mounts. Global West wants these rigidly mounted, metal to metal, but in my case the Moser leaf brackets were slightly deeper than the total height of the leaf pack, so I did need to use spring isolators to take up the gap. In hindsight I'd probably use the necessary thickness lowering block, but for a car that is mostly street, having some isolation there isn't hurting anything.

Installation completed, what are my thoughts? The 600# spring in the front is much more acceptable for a car that is 2000 lbs on the nose. The car feels much more nimble and turn in is crisper. Because I have more bump travel now, even with the stiffer spring, the front glides over bumps and imperfections much better. Although you do notice it is firmer in nature, the ride quality in general is much better.

On the rear-end, it is noticeably stiffer. The Hotchkis springs are a progressive rate from around 150-175 lbs. The GW springs are as close to a linear rate as you can make a multi-leaf spring and they should come in between 180-190#. This is where much of the added ride firmness is now coming from. Again though, because this is a 2" lowering leaf instead of a 3" drop and it uses primarily reverse eye construction to achieve this, you no longer get the crashing effect of the leaf hyper-extending over bumps. To reiterate, the ride is firmer, by a noticeable amount, but the ride quality has also improved noticeably.

The extra stiffness in the rear, is currently the most challenging thing I'm dealing with from a shock tuning standpoint. I'm sneaking up on it, but I'm finding I'm needing much more rebound damping on the rear to control post bump bouncing. That is working to my favor however, because the amount of extra traction at the rear that is apparent is now creating a push at the front. The tendency for abrupt oversteer, especially on power, is completely gone. I haven't tested heavy braking yet, so I can't comment on that.

As rebound is stiffened in the rear, it should create more rotation, which will decrease the amount of understeer. Once I have the compression/rebound thresholds dialed in for neutral handling, I should be able to increase and decrease the compression and rebound in batches to increase overall grip. I'm currently at 6 clicks of compression and 8 clicks of rebound on the front and 4 clicks of compression and 8 clicks of rebound on the rear. Still in the bottom 3rd of total adjustment on these shocks.

Overall I'm extremely happy with this purchase. I'm continuing to fine tune both the ride heights and the shock valving to tailor everything to my usage and driving style. At a total cost of around $3000.00 (including shipping) I sincerely believe I achieved 85% to 90% of the handling benefit that a link style rear would have provided, but at about 35-40% of the cost. Considering I don't competitively track this car and spend 90% of the time cruising around my town, I think that's a fairly decent trade-off.

Some parting thoughts for those of you that are still reading at this point. Would I recommend this level of setup for most of the people on this board that ask about suspension advise? Probably not. While the ride quality is quite good, the leaf springs are expensive when compared to off-the shelf leaf springs and the whole combination is probably a little firmer than the average driver wants.

The Cat 5 bearing system shines specifically off corner, on throttle. If you don't do much in the way of pushing the car in the corners, it's added expense that isn't going to be of much benefit to you. I haven't noticed an increase in noise or harshness, but there's a possibility there since it's a bearing rather than a bushing.

I lean the same direction on the Pro Coils, or any of the competing products from companies like Viking or Alden American. Unless you need to corner balance the car, these don't inherently make the car ride or corner better. A quality conventional coil spring from a company like Global West, DSE, Hotchkis etc. mixed with a quality shock is going to do and you let the ride height land where it lands.

I will say, that adjusting ride height isn't hard, but it's also not that easy. Even with the thrust bearing kit, it's not really feasible to adjust the height without getting the car off the ground and to do it correctly, you really need to have the sway bar detached. So this idea that it's something you're always doing isn't built on reality.

So far, the ride quality from the QA1 shocks has been good and you can feel even minor adjustments in valving, so that doesn't seem to be any type of marketing gimmick. A traditional style single adjustable QA1 shock would definitely make my recommendation list at this point if there's a desire to tweak valving to create neutral handling or to more precisely dial in how you want the car to ride.

No pictures on this one, it's all fairly self explanatory. Thanks for reading, hopefully it's decent information for those looking.