Fixated on replacing rusted up sheetmetal, enthusiasts sometimes overlook the body mounts during the restoration process. However, body mounts are a critical link in overall vehicle performance and should never be ignored. Essentially bushings sandwiched between the body and frame, body mounts maintain body-to-frame alignment and provide cushioning for a smoother ride. From the factory, body mount bushings were almost always made of rubber, and are susceptible to dry rot just like any other rubber bushing. "Combine this cracked, dry-rotted bushing with years of distortion and crushing, and you've got a bushing so deteriorated that they often fall off the vehicle altogether," says Brian. "Visually inspect your body mount bushings for cracking and deformation, and if either of these is present, the bushings should be replaced. Polygraphite body mount bushings provide a stronger link between your body and your frame, reducing chassis flex and improving handling. Most of our Polygraphite body mount bushings feature a strong, zinc-plated steel ring molded into the bushing for added durability and strength."
Factory shocks are a great example of where GM put the bean counters in charge. Factory installed shocks are often simply the least expensive units that were available at the time the car was built. The engineers could never have dreamed of the skidpad numbers that modern performance enthusiasts are able to achieve with today's tire and suspension technology, so to them their choice of a shock wasn't critical. On the other hand, our KYB shocks are a great upgrade from an OE twin-tube shock and are an ideal replacement for an OE monotube shock. For the vast majority of street driven cars, shocks like these are more than enough. For those customers who want a stiffer, more responsive shock, we are working on developing high-performance, non-adjustable shocks for Chevy muscle cars.
Adjustable shocks can be a great upgrade for track cars because they allow compression and rebound to be changed separately. However, it requires expert knowledge to set up, and a lot of trial and error to dial them in correctly. Think about it like a stand-alone engine management system. You don't get a performance advantage just by installing it. The advantage comes from tuning for your specific vehicle. There isn't much of an advantage for a street-driven car because a street car sees such a wide range of operating conditions, requiring a shock that is valved to accommodate any scenario it might encounter, from potholes to perfectly smooth blacktop. You can reap the benefits of an adjustable shock when you're going to see a very narrow, specific set of track conditions. This is why race teams spend many hours setting up their suspensions for each different track. To put it succinctly, a budget, non-adjustable shock performs well in any scenario while an adjustable shock performs exceptionally in a controlled environment, like a race track.
Control Arm Shafts
Although they aren't typically associated as high-wear items, PST's front suspension rebuild kits include new upper control arm shafts for several reasons. According to Brian, some high-mileage cars have worn out the bushings to the point that they have cut into the shaft and make it impossible to get a perfect fit with a new bushing. Likewise, on many cars the front frame cradle has sagged from years of punishment and a heavy engine. "To correct this, our muscle car shafts are offset to allow additional camber adjustment," he explains. "The offset can be oriented on the wheel side for more positive camber, or on the inboard side for more negative camber. Lastly, when a shaft has been in place for 40 years, they can be a real pain to remove. It makes it easy when you can cut your old shaft in half, remove the two pieces, and install a brand-new unit."