bullit

• I am looking to put sway bars(front/rear) on my 69'4dr cut.Any paticular brand or personal experience on this matter?I am slowly starting to work on this thing so I'm glad I found this site.Gonna have a lot of questions!

joe_padavano

At a minimum, the factory 442 bars will fit a 4 door. The stock front bar is 15/16", but the Vista Cruiser used a 1" front bar. You can also find the 1 1/4" front bar from a second gen Firebird, which fits the Cutlass.

For the rear, the stock rear bar tops out at 7/8". Since these cars understeer badly, a larger rear bar must come from the aftermarket. Search for Chevelle parts, they are the same. Be aware that you will need boxed rear lower control arms, or at least you will need to weld the aftermarket boxing plates to the bottoms of your existing arms.

Combine this mod with decent tires and shocks and you'll be surprised at the improvement.

csstrux

does a larger diameter rear sway bar help reduce understeer? I have been wondering about ideal sizes and sources myself.

bullit

thanks Joe for the input,gonna start looking for some goodies

joe_padavano

As a rule of thumb, the "stiffer" end of the car breaks away first. Detroit cars from the 60s and 70s have front sway bars and small or no rear bars. This makes the front end loose traction first when cornering, which is called "understeer". Adding or increasing the size of the rear bar stiffens the back of the car, reducing understeer and eventually leading to "oversteer" - when the back of the car breaks traction first and starts to come around. Detroit felt that an understeering car was easier to control by the majority of drivers (whose training is sorely lacking, but that's a topic for another thread).

Keep in mind that this is a gross oversimplification and things like tire size, spring stiffness, suspension geometry and roll center, etc all enter into the equation. As an example, the front suspension geometry of the 64-72 A-body cars is so bad that increasing the size of the front bar actuall helps handling since the car rolls less and thus the front suspension stays away from the weird tire angles at the limits of travel.

As I said at the beginning, as a rule of thumb, and for a given car with no other changes, increasing the size of the rear bar will decrease understeer.

oldsonharmont

I would like to add a rear sway bar to my '71 Cutlass SX, any advice? Does it just bolt on between the frame? OPGI advertises original 7/8" GM rear sway bars for the A bodies for $154. (thanks)

csstrux

Joe
If you don't mind taking the time. I would like to hear (read) more on this topic when you get around to it, if you were to start a tutorial on mods, and upgrades that are available,as well as their pros and cons, within your experience, that would be great. I would be blowing smoke were I to do so. Thanks, for the info.

71rocket

Good topic. This is something I need.

Steve O

The parts place has the big 1 1/4" front and 1" rear sway bars cheaper than anyone else. I have some on my Green 72 Cutlass. They work great

66 Olznut

Search the local wrecking yards for a late 70's-early 80's Trans Am or Z28. Direct bolt in and 1 1/4" big. Cost me $20 at a local Pick Your Part.

Run to Rund

The factory rear bar is still available #394926 from GMPD, such as www.gmpartsdirect.com (Flow Chevy) for about $90 discounted from list of $154. I have found that 15/16 front with 7/8 still gave oversteer in some cars, so I would consider going bigger in the front as Joe P. suggested and stay with the 7/8 rear. It is harder to get used to oversteer as the back end coming around on you is "disconcerting." A small change in diameter makes a big change in stiffness.

72' Convertible

I just bought a 1 1/8 diameter REAR bar on clearence at Summit but still ahve the stock 15/16ths up front on my 71 convertible. Will that be too much does anyone think? thanks

joe_padavano

That combo will definitely make the car understeer less. Depending on how you drive, it may make the car more likely to spin out. Try it, as these cars are understeering pigs normally. If the car is too tail-happy, consider a 1.25" front bar.