You can try to rationalize it by claiming better aerodynamics or improved handling due to a lower center of gravity, but the truth is most of us lower our cars because it looks cool. Low cars just have a longer, leaner, meaner appearance, which is why rodders and customizers have been dropping them for decades.
Exactly how you narrow the gap between rocker panel and pavement depends on your car's suspension design, available parts, intended use, the builder's skill level, and of course, budget. A torch was the magic weapon back in the day--just heat the coils until they collapse, then de-arch the leaf springs or use lowering blocks to get the tail end down. Today, most of us put a higher priority on ride quality and use more sophisticated solutions ranging from custom springs and dropped spindles to air bags, subframes, and complete custom chassis. Each has its pros and cons.
When the time came to drop my '51 Plymouth Suburban wagon, I set a couple objectives. I wanted to do most of the work myself, which meant limiting heavy welding and fabrication. I also wanted to limit the car's down time since it still sees daily use. Those parameters pretty much dictated modifying the existing suspension rather than reinventing it.
Fortunately, the hot rod aftermarket has solutions. Starting up front, I ordered a set of Fatman Fabrication's dropped uprights. Fatman makes these for a wide variety of '40s-60s vehicles with kingpin- or balljoint-style independent suspensions. Most are designed to provide a 2- to 3-inch drop. The new uprights are fabricated from TIG-welded steel in a process Fatman has been using for more than a decade, a method that founder Brent VanDervort feels is proven and reliable.
Custom coil springs from Eaton Detroit Spring complement the uprights. Eaton has specs on just about every coil or leaf spring ever used on an American car or truck, so they can easily build stock replacements or custom versions to lower yours within reasonable limits. They even adjust the spring rate on custom springs to help prevent bottoming out and optimize handling. I ordered 1-inch lowered coils to help bring the front down further. I also got new 2-inch lowered leaf springs to replace the originals in back.
The new altitude and attitude wouldn't have been nearly as effective with the existing rolling stock, so I also made a trip to the Whitewall Candy Store for some wide whitewall radials. Owner John Zahn says he offers whitewall radials to fit everything from 13- to even 20-inch wheels; I kept things simple and went with 215/75R15 Diamondback Classics that fit the Plymouth's stock wheels and, in my opinion, look right on the car.
While tires and springs are essentially remove-and-replace items, installing the Fatman uprights is a little more than just a bolt-on affair. In most cases, the higher spindle height will require heating and bending the steering arms to bring the tie rod ends back into proper relation to the suspension. However, on Mopars from this era the steering arms can often be flipped upside down and switched side to side, minimizing the necessary bending. The steering arms will still require some machine work to prevent interference problems. Additionally, you'll want to weld on the new upper shock mounts that Fatman supplies with its Mopar kits to improve the poorly engineered factory shock setup. The accompanying photos and captions should help clarify all of this--see what you think.
