I have read tons on this forum and wish to say thanks to all that have contributed. I recently bought a 68 firebird with 2" drop spindles and 2" lowering blocks on the multi-leaf rear springs. I have never been happy with the ride. I switched to a 1.5 inch lowering block to see if that helped reduce tire rub, I will be purchasing leaf springs with less arch to get rid of the blocks in the future.

As far as front suspension I like the look of the 2" drop but have been considering getting rid of the dropped spindles and perhaps going with tubular control arms that allow for a 2" drop while keeping the full travel of the shock. My bushings need to be replaced, and figured now is the time to decide which direction to go.

One question I do have is: Do aftermarket control arm companies recommend doing the Guldstrand mod along with their product? or does the improved geometry of the upper control arm negate the need for the Guldstrand mod? The car is a weekend cruiser, and will never be autocrossed, (by me anyway), so would the Guldstrand mod along with a shorter coils be enough to get the ride i am looking for while keeping some of the lowered stance?

Either way I really need to get the new bushings, but trying to decide how far i need to go.

Any advice is appreciated, thanks.. . .

PS.....Once this is done I can start looking for a Posi axle with something better than 2.56 gears. (I can't find a posi for this gearing)

Steve Davis
1968 Firebird
1970 455 engine

The Pontiac engineers did a great job tweaking the camaro design and improving the suspension. It rides really well in stock form. Set it up like god intended from the pontiac factory and you will have a nice handling specimen of detroit engineering (IMHO)

Hi Steve,

I can't answer your Guldstrand mod question as I have no personal experience with aftermarket control arms. it is my understanding the mod does not need to be done as aftermarket control arms move the ball joint axis to increase caster. Changing the control arms is one modification left on my to do list.

From personal experience, rebuilt stock front suspension, a little quicker steering gear and a fat sway bar really helps the front. I'm running Hotchkis 1 1/2" rear drop springs in the rear. Highly recommend them. Use good shocks. I cut costs using KYB gas shocks but one feels every crack in the road. The stock suspension leave something to be desired especially if running shorter aspect tires. I still encounter some lane change wander with 45 aspect tires. Never happened with 60 series. is ultimately my reason for a future control are swap. Also researching taller upper ball joints.

Don't know if you found the enclosed thread during your search. A wealth of info.


https://firstgenfirebird.org/forums...spension-recommendations.html#Post324673

Another good post.

https://firstgenfirebird.org/forums...g-and-body-hieght-advice.html#Post321109

I hadn't seen this, thanks for pointing me to it,

Steve

Check out Pozzi racing site for suspension discussions.

http://pozziracing.com/first_gen_suspension.htm

The problem with the factory F-body suspensions, regardless if it's a Camaro or Firebird, are lack of positive caster that can be achieve through alignment adjustment, and poor camber gain curve in compression. The latter is compounded if the vehicle has been lowered from stock height (as many are).

The Guldstrand mod does two things, each having their own benefit.

1. Moves the upper control arm rearward
2. Lowers the upper control arm mounting

Moving the control arm rearward increases static caster. This improves straight line stability, return to center steering wheel feel, and increases tire lean as steering angle increases when cornering.

Moving the upper control arm down is changing the pivot point of the control arm and increases negative camber gain.

https://www.motortrend.com/how-to/1510-four-holes-improve-your-cars-performance-in-the-turns/

Many aftermarket upper tubular arms have some added built in caster but can still benefit from more. Whether the Guldstrand mod is compatible may depend on how much total it adds, and/or what is the clearance from the arm to the frame brackets. Also, moving the upper ball joint rearward will reduce clearance between the front tire and the rear fender (especially at the fender bolt). You can gain a little more room by changing the fender bolt to a button head, or remove it altogether. I have a version of the Guldstrand mod with my DSE uppers.

The Gulstrand mod will not change ride height.

Tubular control arms may have added built in caster, but unless they are running tall ball joints (most don't), they won't address the camber gain issue.

Camber gain can only be changed by lowering the control arm mounting (Guldstrand), a taller balljoint, or taller spindle. The taller spindles all seem to come with built in 2" drop. That leaves the tall ball joint or Gulstrand mod. But in actuality Pozzi's testing has shown the the combination of Gulstrand AND tall balljoint produced the best camber gain. http://pozziracing.com/proforged_first_.htm. However, this increases bump steer. This can be corrected with a taller outer tie rod.


Since you're looking at doing both front and rear, you might want to look at Ride Tech's Street Grip suspension. The only thing it doesn't address is the tall outer tie rods. It has dual rate front springs along with adjustable shocks should give it a decent ride, while significantly improving handling.

Forgot to mention, fixing the camber gain has another benefit besides transforming the handling. Because the tire gains camber as the tire moves closer to the fender, it actually reduces the propensity to rub when running wider tires on front.