This chassis is designed to understeer . That's why front end geometry is so important on this chassis.
Long answer short, you can cheat poor geometry by limiting suspension travel. 5660 is stiffer and would help with understeer, a bit.
Also rear bar should be about 70% the diameter of the front bar to help with your setup.
Changing just the upper A arms can only do so much. The length and offset of the arms has very little effect on camber change, roll center or overall handling. They add + caster which can make the car track straighter at speed and improve turn in. However too much can make the car feel vague and the steering sluggish so that only goes so far. As the + caster is increased there is a tiny improvement in camber as a side effect when the wheels are turned. Our upper arms have this benefit as well as more caster adjustment. To make any profound improvement in the suspension geometry of cars that need it the actual pivoting points (pickup points) that determine that geometry need to be moved vertically. Road race cars like SCCA, TransAm, LaMans Series race cars and fast DRAG CARS use special taller spindles, raising the upper ball joint pivot points like our Stage 1 and 2 packages do. This was the genesis of our pro Touring Tall Spindles for the GM A and G Body and S series Truck platforms. For years circle track racers that run stock G or F body chassis have used taller truck upper ball joints, which seated improperly to improve the geometry. They’ve been doing this kind of thing for years by fabricating new parts, mixing and matching stock parts, modifying suspension/frame mounts etc. That’s how to win races with a less than perfect factory chassis and a small budget. We’ve taken that race experience, applies new technology and brought it up to date with our SSM STAGE 2 package. Major suspension improvements, not just shiny parts.
They'll physically bolt together and you could drive the car around but there's a catch or two. There's the fact that the original arms on the A and G-Body as well as the S series GM Platform cars were originally designed to droop down over the frame and have the ball joints at the proper angle for a full range of travel. Once you lower the car, go to taller spindles or ball joints etc. the arms end up closer to level and the ball joints end up close to binding at ride height. Hitting a big bump can bind up the ball joints and put a tremendous amount of stress on them as well as the upper A arms and A arm mounting bolts. They'll only take that for so long before something fails...
Much of it also has to do with alignment. A lot of folks think if their car goes straight and doesn't chew up the tires that it's aligned properly and working as well as it can. They're kidding themselves and they're missing out on a LOT of performance. The alignment specs recommended in the `60s and `70s (and even `80s!) were anything but performance oriented. In fact they've changed little since the 1940s. Today almost every car is using power steering and we're all running high performance radial tires (except for the resto guys but that's another story...) these tires are often more than twice the width of the originals, we've also got another 40 years or so of experience to draw on. What's more, once we've corrected the geometry so that it works like a new performance car it demands the same type of alignment those cars run to achieve peak performance.
Modern performance cars run a LOT more + caster and - camber. The + caster helps the cars track better at highway speeds and gives better steering feel. The - camber helps keep the tire's contact patch flat on the road surface during cornering. It's part of what makes new cars drive like new cars. Using these kinds of settings on older cars yields a BIG improvement in drivability and performance but because they were designed around different specs it's usually impossible to attain the best numbers with stock parts and shims. Lowering the car or increasing the effective spindle height with taller spindles or taller ball joints all add more + camber making it ever harder to dial in a - camber setting (which is what we want). That's the big reason for different upper arms. The taller spindles or tall ball joints make the big geometry improvements and the proper upper A arms make it possible to combine the new parts and geometry with the proper performance alignment, an unbeatable combination!
WHAT IS THE STAGE 1?
The SSM Stage 1
The secret is the combination of the extra tall ball joint to match your new tubular upper arms which greatly improves the camber curves and relocates the roll center. This means more grip and less body lean. The 1" EXTRA tall upper ball joints reverse the backward factory camber curves for a huge increase in grip. They also raise the extremely low factory roll center to dramatically reduce body roll
· For stock and lifted cars this radically corrects poor ball joint angle and helps the arm clear the frame when lifted properly.
· For drag racers SSM Stage 1 Plus allows faster weight transfer and more positive caster for better top end stability.
WHAT IS THE STAGE 2?
The SSM Stage 2
The stage 2 goes even a step beyond the Stage 1 Plus and further corrects the terrible backward geometry of the factory front suspension, by using Racing Series ball joints, the ONLY ball joints made 100% from US materials in the USA!
They are much stronger, smoother, and longer lasting, than original GM, or any other aftermarket ball joint. The .5" taller lower ball joints further improve the camber curves and roll center location, significantly reducing lateral roll center migration for more predictable behavior.
They also correct the factory bump steer issues by raising the tie rod ends into proper alignment. Now with extremely improved geometry designed for the rigors of SCCA, TransAm and NASCAR your car will truly dominate the street and track!
PRO TOURING TALL SPINDLES?
The SSM Tall Pro Touring Forged Performance Spindles for the A and G-Body as well as the S series GM Platform. Raises Roll center, lowers center of gravity, eliminates bump steer and creates a negative camber curve that surpasses the C7 Corvette. Uses larger bearings with a wider separation and will accept 11-14 inch rotors. Huge single piston to 8 piston caliper options as well. Bolt on fast ratio steering arms. Even the ball joint tapers are larger. Available in stock and lowered heights.