Here is our '53 Pontiac shown...        read full caption Here is our '53 Pontiac shown in a state of mock-up. We not only lowered the car all the way down where it will sit when the air springs have been deflated, but also carefully blocked up the '56 Chevy rear bumper to give us an idea of how the car will look when finished. Mocking things up this way takes a while, but is time well spent.

The Air Ride Technologies...        read full caption The Air Ride Technologies triangulated four-link kit comes with brackets designed to accommodate many different chassis configurations, but these brackets can be modified or used as reference to fabricate new mounts to better suit your application. Besides the black powdercoated finish shown here, the kit can also be ordered with polished stainless bars.

As if we needed one more reason...        read full caption As if we needed one more reason to update the suspension, check out the original leaf spring packs. The driver side had two leaves that were broken and separated-these just happened to be the main leaves. This not only let the car sag, but could have been highly dangerous on the road.

To start the installation,...        read full caption To start the installation, we first determined the desired ride height where the car will be driven under normal circumstances. Then we raised the car onto jackstands, maintaining our front-to-rear ride angle. Then the rearend went on another set of jackstands to match the ride height as if the car were sitting on all four tires.

If you've been paying attention to the last few issues of Custom Rodder, you may recognize this '53 Pontiac from tech stories where we installed a Fatman front frame stub and chopped the Poncho's roof. To keep the progress flowing in the right direction, it's time to put some similar thought and energy into the rearend and how to get the best possible ride, handling, and stance.

We knew the Pontiac was going to raise and lower via Air Ride Technologies air springs(the Fatman IFS is already equipped with ShockWaves), and that the owner, Don Escoto of Riverside, California, wanted it to sit as low as possible at its driving ride height. Keeping all that in mind, it was an easy decision to do away with the original leaf spring rear suspension. Sure, we could have used the existing springs in conjunction with airbags, but achieving that super-slammed stance would've meant removing most of the leaves and allowing the car to sag to the desired ride height, which we felt would have compromised handling and strength. Yes, it could be (and has been) done like that, but why put all the time and energy into building a sweet-looking, reliable sled without constructing a solid foundation to support it for many trouble-free years to come?

Considering Don's desire for an ultra-low yet functional stance, we'll be doing significant reconstruction not just on the suspension, but also the frame, floor, and inner fenders. Our approach is to determine a driving height, then choose and mount the suspension to achieve that stance. We decided to use Air Ride Technologies' triangulated four-link suspension. On a triangulated four-link, the lower control arms run parallel to the frame, keeping the rearend from moving front to back, while the upper two arms are mounted on angles to prevent the rearend from moving side to side, eliminating the need for a Panhard bar. Using a four-link-style suspension not only allows the car to move up and down without restriction, it can also improve handling capabilities considerably when properly set up.

The Air Ride Technologies Air 4-Link is a generic system (specific-fit kits are available for certain popular models), so our first step was to inspect the trunk floor, inner fenders, and frame for potential clearance problems or places that needed major modifications. In this case, we pretty much had to modify all of the above. Most installations will not require as many mods as you see here, but if you want to drive your ride as low as possible all the time, like this Pontiac, read closely and you might pick up a few ideas.

Even though this kit will work on just about any type of vehicle, keep in mind that an installation of this level should be done by an experienced welder, as well as someone with the patience to triple-check everything along the way. You will need a good level, degree gauge, cutting torches or a plasma cutter, and a good welder like our HTP America MIG 140. Experience with suspensions is a plus, but as long as you have a good handle on your welding skills and can read a degree gauge, you will find this kit is engineered to install relatively easily. Air Ride Technologies has spent a lot of time designing these kits to not only work properly for the life of your car, but also so the backyard builder can achieve the same results as big-dollar shops.

Next, we cut out the trunk...        read full caption Next, we cut out the trunk floor and a portion of the floor directly under the back seat. This was quick work with our plasma cutter, but a reciprocating saw, cutoff wheel, or even an acetylene torch will do the job. Don't forget to remove the fuel tank and fuel lines before throwing any sparks.	Because this car was slated...        read full caption Because this car was slated for an extremely low stance, we built a notch in the frame to allow more rearend clearance. We also added a beefy crossmember to add strength and act as a base for mounting the upper airbag and shock mounts. The vertical square-tube supports are temporary and will be removed when the floor is replaced.	At this point we could start...        read full caption At this point we could start positioning the rearend to mount the four-link. First it was centered in the body, then we rotated the pumpkin until the driveshaft yoke was leveled to a zero-degree angle.
With the frame and rearend...        read full caption With the frame and rearend leveled from side to side, and the car sitting on the desired front-to-rear rake, the upper and lower control arms and brackets could be tacked into place.	This is best done using a...        read full caption This is best done using a level to make sure the control arms and mounting brackets are set square. Air Ride Technologies includes detailed instructions for these important steps.	We first mocked up the upper...        read full caption We first mocked up the upper arms to mount off the rearend's center section, which positioned the arms in the opposite angle seen here. In that arrangement, the frame mounts would have interfered with the rear seat, so we reversed the mounting positions. Either way will work fine as long as the arms have enough angle to keep the rearend from moving side to side. The only problem was that we had to build a new crossmember to mount the upper arms. This would not have been an issue if the car's ride height wasn't so low.