With the ‘60s and ‘70s muscle car prices out of reach to many automotive hobbyists, there’s a growing market for parts to hot rod older pickup trucks. Two generations of GM’s fraternal twins, the Chevrolet C10 and the GMC C1000, are popular choices from the model year 1967 through 1987 among enthusiasts.
Even though GM made significant design changes from the old leaf-spring and straight-axle configurations of the previous generations, suspension upgrades for these trucks are critical to achieving optimum ride and handling or controlling power from late-model engines under hard acceleration. Both Total Cost Involved (TCI) and Heidt’s Hot Rods And Muscle Cars offer front and rear suspension kits that will enhance steering, provide more adjustability, and overall, strengthen the chassis.
“C10s are plentiful, and there are a lot of variations,” says Vaughn West of Heidt’s. “Entry-level prices on them are cheaper than a lot of the standard ’40s and ’50s trucks. You can do a lot of great things with them, and the aftermarket has actually been picking up with a lot of product offerings.”
“I’ve seen the popularity of the C10s skyrocket. I think it’s because GM made so many of them,” adds Mario Salgado of TCI. “At one point, they were so easy to get, and it was a low-cost alternative. They ride so much better than the earlier straight-axle trucks.”
Big Changes In 1960
In 1960, Chevrolet introduced a new drop-center ladder-frame for its full-size trucks. It incorporated an independent front suspension and a trailing-arm/coil spring/Panhard bar arrangement in the rear. Some trucks could be ordered with auxiliary quarter-elliptical springs mounted behind the axle for more payload and towing support, and 1-ton models had the traditional leaf-spring setup. This generation pickup truck also saw the first appearance of a new model-designation system that dropped the previous 3100, 3200, and 3600 badges worn by the venerable 1955 through 1959 Task-Force-era vehicles.
Under the new system, the letter “C” was used for two-wheel-drive models, followed by a 10 for ½-ton models, 20 for ¾-ton, and 30 for 1-ton versions. The letter “K” was used for 4WD models, followed by the same numerals for payload designations. GMC followed suit with a twist, using respective designations of C/K 1000, C/K 1500, and C/K 2500.
In 1967, Chevrolet released its most significant truck restyling to date, with a lower, sleeker profile, and offered new features such as carpeting and bucket seats in its Custom Sport Truck option. Hence, this time frame is often referred to as the Custom Sport Truck era. Another major redesign came in 1973, and that generation lasted through the 1987 model year before the ground-breaking GMT400 platform was introduced in 1988.
The ’67 to ’72 and ’73 to ’87 generations of Chevy and GMC trucks sold millions, and many have survived to be restored and modified. “They just look good when they’re customized,” reminds Salgado.
Both Heidt’s and TCI offer front and rear upgrade kits for the ’67 through ’87 trucks. The front kits feature tubular upper and lower control arms with coilovers and a rack-and-pinion steering conversion. In 1973, Chevy moved away from trailing arms and coil springs, utilizing leaf springs. TCI developed a torque-arm/coilover suspension for the ’67-’72 models and a four-link/coilover system for the ’73 to ’87 models. Heidt’s has a four-link/coilover kit that covers all the model years from ’67 to ’87.
Welding Not Required
Nothing good is ever easy, and there were challenges in developing these suspension kits.
“The biggest thing was figuring out what the customer wanted. We were looking at the guys wanting to put big drag radials on these trucks as well as those Pro Touring them,” says West.
“There were always challenges because GM didn’t have the best quality control back then,” adds Salgado.
One common denominator between the kits from both manufacturers is that welding is not required for installation.
“Yes, the goal was to keep it as bolt-in as possible,” says Salgado.
“We tried to make it as simple as possible,” echoes West. “We utilized as many pre-riveted or bolted holes in the frame rail.”
Some sections of the frame may have to be cut, and there will be grinding to clearance some parts. Also, a few holes may have to be drilled or enlarged, but no special tools are required for the installation. While a good set of hands, power tools, and a shop lift are most useful, these installations can be completed by an experienced mechanic, or with the help of a few friends in a home garage.
Here’s a closer look at each of the kits:
Heidt’s Front Suspension
The basic design features unequal-length upper and lower tubular A-arms with rack-and-pinion steering and coilovers, although an air suspension can be substituted. The kit can be ordered with or without dropped spindles, and with different spring rates. Numerous disc-brake options are also available. The entire setup – which includes engine mounts – is built around a new crossmember. The system completely replaces the old crossmember. All the old steering gear is removed as well, including the steering column if the truck uses a manual transmission.
“When it comes down to it, obviously, it’s best to change out the steering column on these trucks,” says West, noting that engineers did borrow some of the geometry strategy from the company’s classic truck products. “We did change things we found that weren’t going to perform well with a larger vehicle like the C10. It isn’t like a Mustang II that everybody has. The crossmember and arms were designed and developed in-house by our engineers. It’s not a Mustang II, it’s actually a very different geometry.”
TCI Front Suspension
TCI’s frontend kit follows the same design strategy with unequal-length tubular A-arms, coilovers, and rack-and-pinion steering. An airbag option is available, as are numerous brake choices. TCI says the kit slims down the truck’s nose weight by 72 pounds, and suspension travel is not reduced.
“We wanted to keep the suspension travel. You see these guys with static drops all the time, and they’re sitting on the bump stops. With ours, you don’t get that. We wanted to get a good static drop, but still be able to drive it,” says Salgado, noting that there is an initial 5-inch drop with the front suspension and another 1.5-inch adjustment with the coilovers.
TCI Rear Suspension
TCI offers two different designs for the rear: a torque-arm/coilover arrangement geared towards the ’63 through ’72 trucks, and a four-link/coilover for the ’73 to ’87 models.
“There are minor differences between trucks with long and short beds in regards to the rear frame. Upgrades are being done to make it easier for the long-bed guys,” says Salgado. “With the short bed trucks drying up, there is more emphasis on long beds. We’re making changes as needed.”
Even though the trailing arm suspension is the foundation for today’s NASCAR rear suspension design, either the torque-arm or the four-link will be a considerable step-up in ride and handling quality over the stock C10 setup. The torque-arm offers three height adjustments, and then there are fine-tuning adjustments with the coilovers. The factory axle housing or 9-inch replacement can be used.
The four-link is also designed to improve handling and can be used for autocross racing. Again, there is no welding involved — not even the bracket for the axle tube. There are anti-roll bar and airbag options for both kits.
Heidt’s Rear Suspension
Heidt’s strategy is to offer a four-link for both generations. Leaf-spring vehicles require a little bit more fabrication to make it fit correctly. The kit can be ordered with axle brackets or a Heidt’s rearend housing. Other options include gas shocks, different-rate springs, drum or disc brakes, and airbags.
“We built in a certain geometry. Many of our customers are just starting out, so if you add a lot of capability to adjust the length and change instant center, they can be overwhelmed by all the options,” says West. “We’ve been playing around with the parallel four-link for 25 years. Maybe the biggest challenge we had was the placement of the Panhard bar bracket.”
Ride height is still adjustable via both the coilovers and shock mounts.
Working With The Companies
Both Heidt’s and TCI admit there are some inconsistencies among the two generations of Chevy and GMC trucks. This was a time when dealers could order different rear suspensions. In other words, even if a GMC normally came with a leaf spring, the dealer could order a coil spring setup — and vice versa.
It’s important the customer provide every detail possible when discussing options with the company tech representative. The total installation cost will depend on options and shop rates. Officials say an experienced hot rod or 4×4 shop can install the front or rearend kits in about 10 hours.