When the General designed the early Chevelles, and even the later ones, they weren’t building track cars. Instead, their goal was to churn out basic, affordable transportation for the masses. And, even when they did stuff in some performance application, it was typically confined to driveline upgrades. When it came to the suspension, their goals were low cost, ease of manufacturing, and durability as it related to the warranty. They weren’t building uber-strong race car parts since most people buying Chevelles were picking up groceries and not time slips.
Given those facts of life, GM equipped their A-bodies with stamped steel arms that fell into the “strong enough” category with pinion angles that were in the general ballpark. Add in the fact that well over 40 years have passed and not only do we have better technology today, but those factory installed parts are really starting to show their age.
And while the stamped steel parts were fine for cruising around, they tend to flex under hard use, which causes wheelhop and lost traction due to geometry changes. The easiest solution is to ditch the flimsy stamped steel parts and replace them with much stronger modern replacements. For this exercise, we dove under a fairly bone stock ’65 Chevelle and swapped out the rear parts with a kit from PMT Fabrication. The install was easy and will pay off big time once we up the output from the 350ci small-block under the hood and start mashing the loud pedal at wide-open throttle.
Here's our starting point, nothing special, just stock rear suspension parts under a 48-year-old Chevelle.
The lower trailing arms are hand TIG-welded from 1.500x2.500x0.120-inch wall rectangular tubing and came with the graphite impregnated urethane bushings already installed in the ends.
To accommodate the included trailing arm braces we used the supplied, extra-long, Grade 8 bolt in the forward mount holes.
Installation was a snap. We simply supported the rear housing with a pole jack, unbolted the shock, removed the stock lower trailing arm, and then installed the new PMT arm. We made sure the sway bar mounting holes were to the rear and the zerk fittings were facing down.
With everything in place we then went back and tightened up all the fasteners. We also made sure to hit all the zerk fittings with a grease gun. Total install was under two hours.
The trailing arm mount braces are designed to strengthen the upper crossmember by triangulating the whole rear suspension. The result is a more stable system under hard acceleration and cornering. They came with the kit, but PMT also sells them separately for $110.
And here's the brace integrated with the lower trailing arm. One thing we really liked about the kit was that it came with all the necessary hardware needed.
The hardest part of this installation, or any Chevelle rear suspension upgrade, was removing the old bushings from the rearend housing. We used a large C-clamp tool to get it out, but a hammer and a large socket works as well.
The polyurethane Energy Suspension bushings supplied with the kit can be ordered in either red or black and are a lot more stable compared to the stock rubber pieces.
The bushings rely on an interference fit to stay in place; we used a large hammer, but later we found that PMT offered a slick bushing installation tool for 35 bucks.
And here's what the bushing looked like completely pressed into place.
Here you can see why the TIG-welded chrome moly upper control arms are so much stronger than the stamped steel arms they replaced. In addition they were adjustable so we could dial in our pinion angle.
We set the arm's length to match the stockers and then put them in place. This got us in the ballpark and we can fine-tune them later.
The suspension kit also came with a powdercoated rear sway bar.
Typically installing a rear bar onto a car that didn't originally have one is a bit of pain and involves U-bolts, bushing mount pads, and host of other hardware. However, in this case it was super easy since the bar simply bolted to the holes in the lower control arms.