1967 Pontiac Firebird Suspension Upgrade - Suspension Ascension
Modern technology has vastly improved the ride and handling characteristics of vintage Pontiacs, and the various high-dollar packages we see today often combine coil-over- and/or air-spring-type suspension systems with large aftermarket wheels and tires.
Those who have successfully installed these systems onto vintage Pontiacs enjoy their effects. They might consider vintage suspensions ancient technology and wonder why any hobbyist would attempt to improve upon it. There are, however, a large number of budget-minded hobbyists who much prefer expanding upon the existing design, while maintaining original appearance-and that describes us.
The Assessment
Our '67 Firebird convertible has been the subject of past HPP articles, and much of its suspension remains unmodified since its purchase in 2000. When compared to our Second- and Fourth-Gen Firebirds, our First-Gen's original 0.688-inch front sway bar and front coil springs, aftermarket front and rear shock absorbers, stock multi-leaf rear springs (to replace the mono leaf), and no rear sway bar leave much to be desired.
We never intended for this particular Firebird to be a corner carver, and instead performed a sheetmetal restoration with the hopes of creating a drop-top cruiser boasting predictable road manners. The result, however, was a beautifully-painted Firebird that dipped so severely over normal street imperfections that its near-stock-sized front tires rubbed the top of each inner fender well. Body roll was so severe that it caused erratic understeer when pushed moderately into normal turns, lending to its appetite for front tires.
There was noticeable improvement after installing urethane body bushings, a pair of modified sub-frame connectors, and 15x7-inch Rally II wheels with modern 235/60-sized rubber. It wasn't long after that we realized our Firebird's original suspension simply wasn't suitable for normal street duty. We began considering all available options, but had two major stipulations throughout the process-our choice had to maintain stock-type appearance, and it had to be at an affordable price.
Decisions, Decisions
Our past experience with urethane bushings has shown positive long-term handling improvements when compared to rubber, without compromising stock appearance. We also felt that a larger front sway bar, and the addition of a rear bar, would be an easy way to positively change our Firebird's attitude. We decided to follow our instincts, and started visiting various Web-based forums, searching for present offerings.
One of the companies frequently mentioned was Performance Suspension Technology in Montville, New Jersey, so we contacted its technical department seeking suggestions. We explained our objective, and were told that a 1.125-inch front- and 0.875-inch rear sway bar kit should provide substantial improvement, and that combining these pieces with a host of other components would give our Firebird a significant attitude adjustment.
Following the company's recommendations, we ordered its suggested G-max front and rear sway bar kits with Polygraphite bushings, a Polygraphite control arm bushing set, KYB Gas-A-Just performance shock absorbers with Polygraphite bushings, Ground Zero front coil springs, and a Polygraphite rear traction arm ("radius rod" in Pontiac speak) bushing set. The entire purchase set us back around $825, which included free shipping to the lower 48 states, and everything arrived on our doorstep within a few days.
The Install
Installing the front-end components, four shock absorbers and radius rod bushing set was very straightforward. We simply removed the originals and installed the replacements. The rear sway bar kit was, however, slightly more difficult. The supplied drop-down links that suspend from the framerails wouldn't work with our particular Firebird, so a quick call to PST's technical department netted us a pair of revised links, available upon request.
With the entire installation complete, we backed the Firebird from the garage and immediately ventured to our local repair shop for a front-end alignment. It took only a few blocks for us to notice the positive effects the new suspension components had made-normal bumps were no longer an adventure, and body roll had appreciably decreased. It was obvious that our Firebird's suspension was now completely functional, and the car was much more pleasurable to drive.
The Comparison
No article focusing on suspension would be complete without some type of back-to-back comparison. A 600-foot slalom seems most common, but after consulting with a local friend who autocrosses regularly, he advised that a 200-foot slalom course-consisting of six consecutive rubber cones placed 40 feet apart-would keep speeds at a minimum. That proved a sound suggestion, considering how unpredictable our Firebird was in stock form. With the cones and timing equipment set up, we were ready to establish a baseline.
We found that the Firebird had a tough time negotiating the turns. It plowed severely at moderate speeds, and wasn't reacting to driver input. Attempts at varying tire pressure seemed to do little, as the vehicle's weight was simply too much for the front 235/60R15 tires to handle at higher speeds. Understeer was so severe that we had to abort a number of runs after passing the first few cones. We were, however, able to complete a few lower speed passes, and with an experienced driver behind the wheel, recorded a disappointing best of 19.16 mph.
With the PST components installed, the Firebird negotiated the turns of the same 200-foot slalom much more predictably, and at much higher speeds. It remained flat when diving into each turn, and it reacted better to driver input. Through the same course with the same driver, the Firebird upped its speed just under 5 mph, increasing to 23.96 mph over 200 feet. It was still obvious that the Firebird's stock-sized street tires were holding it back, but the marked improvement clearly indicates the positive effects the new suspension components made. Bear in mind this was accomplished by simply installing a larger front sway bar, adding a rear bar, KYB Gas-A-Just shocks, new front springs and polyurethane bushings. The complete steering linkage, ball-joints and rear springs remained, and the same tires were used before and after.
Though our installation was drawn out over several weeks for various reasons-and some specialized equipment was required-it seems an installation such as ours, when working a few hours each night during the week, and several hours over a weekend, should take an average hobbyist around one week to complete.
After spending a number of miles enjoying our Firebird's new attitude, we've since looked back on the situation, wondering why we waited so long to address its suspension-related issues. While it's not likely that all vehicles will see such improvements, PST offers a wide range of affordable components that are sure to improve the ride and handling qualities of most any vintage Pontiac to some degree. There's no denying that our low-buck investment has paid huge dividends-and that's the exact combination we were after!

Suggested Torque SpecificationsFront Control ArmsTorqueLower Control Arm Mounting Bolts80 lb-ftUpper Control Arm Cross Shaft-to-Frame Bolts50 lb-ftUpper Control Arm Cross Shaft End Bolts35 lb-ftFront Sway BarFront Sway Bar Mounting Bracket Bolts15 lb-ftFront Sway Bar End Links8 lb-ftShock AbsorbersFront and Rear Shock Absorber Upper Studs90 lb-inFront Shock Absorber Lower Bolts20 lb-ftRear Shock Absorber Mounting Plate-to-Body Bolts40 lb-ftRear Shock Absorber Lower Studs45 lb-ftRear SuspensionRadius Rod Front and Rear Mounting Bolts 80 lb-ftRear Sway Bar Leaf-Spring-Mounting-Plate-Bracket Bolts 35 lb-ftRear Sway Bar Drop-Down Link Bracket-to-Frame Bolts15 lb-ftRear Sway Bar Drop-Down Link Upper Studs8 lb-ftRear Sway Bar Drop-Down Link-to-Sway Bar Bracket Bolts 15 lb-ft
Components Ordered For Our '67 Firebird ConvertiblePartPriceG-max 1.125 Performance front sway bar with Polygraphite bushings$189G-max 0.875 Performance rear sway bar with Polygraphite bushings$189Ground Zero front coil springs$155Polygraphite control arm bushing set$99KYB Gas-A-Just performance shocks$159Polygraphite shock bushings$10Polygraphite rear traction arm bushing set$22Total$823Further savings are available if components are purchased in a complete package.

Photo Gallery: 1967 Pontiac Firebird Suspension Upgrade - High Performance Pontiac Magazine

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