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Altitude Adjustment!
Published: 2/28/2001  
Author: Paul Romanych a.k.a. RedSS
How to lower your SS the right way What was GM thinking when they designed the 454SS suspension years ago? Perhaps the owners would actually take these trucks offroad? Perhaps they would not drive them like an SS-badged vehicle was intended to be drive

What was GM thinking when they designed the 454SS suspension years ago? Perhaps the owners would actually take these trucks offroad? Perhaps they would not drive them like an SS-badged vehicle was intended to be driven? Well, thanks to the aftermarket, owners of these trucks have an abundance of parts available to get that stock mud-bogger down to a streetable height and put the "sport" back in Super Sport. Not only that, but a "dropped" (or lowered) truck just looks cool, and is the main ingredient in cooking up a hot sport truck.

First lets go over the main components of the suspension system that will be modified. In the front, you have a set of coil springs and shocks, which handle the load, and are located between a mount on the frame and the A-arms. On the outermost portion of the A-arms are located a set of spindles---one for each side. Your brake discs are mounted to this spindle on bearings, and the wheels to the discs. Located on the spindles is a mount that the steering tie rods connect to, to enable steering control. In the rear, there are shocks and leaf springs, which handle the load, and shackles and hangers to mount the leafs. Shackles are about two hand widths and about 4" deep in size and bolt directly to the frame. Hangers bolt to the shackles, are about 2" long, and bolt to the leaf springs to locate them. Hangers provide the horizontal movement the leafs need when they de-arc under load which is why you cannot bolt the springs directly to the frame or shackles. I will also note that while there are many combinations available of ride height kits, this article will discuss the most popular: leveling, 2/4 drop, 3/5 drop, and 4/6 drop. For duallies, which typically are the C/K-2500 and -3500 with an extra 1" lift over the C-1500, there is also a commercially available kit for a 5/7 drop. But you may assemble parts in any combo you choose, be it a 1/2 drop, 2/3, 4/5, 3/3, 4/4 and so forth so long as you do your research and buy the right products. Nor will this article venture into air bags and hydraulics land. Also it is imperative to use quality stuff like Bell-Tech components.

Now that you are a suspension expert, decide what you want to modify. Lets say you don't like the look of the 2-inch rake that most trucks are built with. Manufacturers build trucks with an extra 1-3" height in the rear end as they intend for their trucks to haul stuff---stuff that will, when loaded in the bed, make the truck look like it is sitting level or close to. But who honestly uses their sport trucks for hauling hundreds of pounds of crap? Only a few kids who can't afford a work truck. So, you lower the rear end. Not too hard. This is accomplished with a set of lowering shackles OR hangers (not both---this will give you 3"-4" of drop), which should run you about $150. This will level a 454SS and nearly every other c-1500 out there. Since the 454SS and other c-1500's came with the same leaf springs, hangers, and shackles that a standard c-1500 comes with, you may use any one of the available c-1500 shackle kits on the market. Shop around for a good kit. Kits are available for 1" and 2" drops, depending on the length of the shackle or hanger. To install these parts, lift the rear of the truck by the differential, support it on the frame by jackstands (the 454SS is heavy…don't use cheapie Jap-stands intended for your econo-commuter). Keep the jack under the differential, and lower it to take weight off of the springs. Then swap parts. Remember to torque to recommended specs and use a very little #242 Loc-Tite to secure the threads. Suspension parts are subject to a lot of vibration and movement. It is a good idea to re-torque after 10, then 40, then one hundred miles to make sure all is tight. While you're under it, if you have a high-mileage truck, check your rubber bushings for wear.

Still think your truck is in the clouds? Well now it's time for a more radical change in ride height. The typical 2/4 drop (2" drop in front, 4" drop in rear) will also level your ride height but get the truck an overall of 2" lower, which is still a great choice for a daily driver as you lose little clearance, and do not have to notch the frame in the rear (more on that later). This is accomplished in the rear by installing a set of 2" drop hangers and 2" drop shackles. The installation is fairly straightforward. Replace the rear components as described earlier, only this time you replace both the shackles and hangers, and the shocks as well (shocks do not give you any more "drop", but are shorter so they work with lowering components). Note that with this much rear drop, the angle of the driveshaft to the tranny and differential is changed. This must be addressed. How? You loosen the u-bolts holding the axle housing to the springs and slip the included shims underneath the spring plate from the back of the axle housing. Then move to the front. Jack up the truck, and place jackstands under the frame. Now you have a choice: 2" drop spindles, or 2" drop springs/shocks. Done with good shocks and springs (NOT your old springs with a coil or three taken out) like Doestch-Tech Slam R's or Bell-Tech Nitro Drop shocks with Belltech springs, ride height will be a little stiffer, but not poor. You retain some clearance from the ground to the A-arms with the springs/shocks, but you retain the ride softness and feel of the stock suspension by swapping in spindles. Your call. Remove the wheels as these are only going to get in the way. Now place the jack under one A-arm. Lift it 1" or so to put a little "set" in the spring. Note: the 454SS does not share front suspension components with the normal c-1500. Stock springs are lower. Brakes are larger. Spindles are heavier-duty. Make sure you tell your sales rep that the kit you want is for a 454SS and not a standard c-1500.

For spindle swaps: remove the brake calipers, discs and bearings. Make sure the components are not worn; if so, fix as necessary. Unbolt the tie rods and let them hang. Finally unbolt the remainder of the spindle mounts. Reassembly is the reverse of removal; use fresh wheel bearing grease on all moving parts, especially the spindle end. This is also a good time to repack the wheel bearings. For spring/shock swaps: unbolt the spring mounts, as well as the lower shock mounts. Release the jack VERY slowly, until the spring may slide off. Remove the spring and remaining shock. Then replace with drop springs and shocks and reassemble. During reassembly, jack the A-arm up a little again before you mount down the spring. Now with the spring job done, this will result in the geometry of the front suspension being "out of whack" so you need to have an alignment done. For spindle swaps, there is no re-alignment needed but it would not hurt just to check before you end up needing new tires 5,000 miles after just replacing them.

Still not low enough for your taste? You may do a 3/5 drop. This will involve a combo of 1" drop springs/shocks and 2" spindles, or, 3" drop springs/shocks in front, and a set of 2" drop hangers and 3" drop shackles in the rear, with drop shocks, with the appropriate axle shims. This is the lowest you can go in the rear without frame mods. As it is you will probably have about 2" of clearance to the frame, sans bumpstop. With the stop you might be lucky if you have ¾" to 1". Get a shorter bumpstop. Drive slowly and stay off of the rough roads.

Or, modify the frame with a c-notch kit. Now you are getting into the weekend-cruiser-only territory. Unless you live in a very well maintained area or your truck is not your primary vehicle, this 4/6 or lower drop is not practical. 2" drop spindles along with 2" drop springs/shocks are the ticket for a front lowering job, while an axle flip kit is the ticket for the rear. While the procedures for the front are the same as previously described, the rear is a bit more involved. You are relocating the differential above the leaf springs, between the frame rails and springs (like most cars…in your truck, as stock, the differential is below the springs). This involves cutting and reinforcing the frame, which is called "c-notching". In the kit, you are given basically a template to draw on the frame and cut out, a reinforcing plate to bolt on in place, new differential u-bolts, and a pair of shocks. You re-use the stock hangers and shackles. This is too detailed to get into for this article, but it involves lots of disassembly, welding, moving parts, and cutting so if you are not up to the task, have a shop do it. It can be done in the garage on a rainy weekend however, if you have the tools and are competent.

After you have these parts installed your truck will look like it was intended to---a sport truck. No more offroad themes, and no more mud-boggin'. Now that is one hot dish of American muscle.






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