Hello,

I recently rebuilt my front suspension and when with the polyurethaine bushings with new tie rods ***** joints and all that good stuff.

I am now getting ready to do the rear and am really considering adding the boxed lower control arms and rear sway bar from the 442 and replacing the bushings with the poly ones as well. My question is there anything extra that needs to be done and should I upgrade the upper arms as well and is there any down side to this project? Or can just the lower arms and sway bar be added with the stiffer bushings for a great feel?

 

The rear lower boxed arms and sway bar is a great addition; I will be doing all that some time in the far future (along withthe front)...

Since you have it all apart, you mightaswell replace the bushings in the upper arms.
There are frame stiffeners you can add if your car did not come from the factory with a 455. They connect the frame to the upper arm mount. Not sure now much benefit they would be with a 350...

I heard to do one arm at a time for ease in installation / reinstallation as diffs are heavy.

As for the installation, I have not done this but I would love to hear your opinions and ratings of the job as a whole and the quality of the ride.

I have been debating between rubber vs poly for years and just get confused at which to use... I have heard equal pros and cons on the average.

 

Unless you go with aftermarket arms with spherical bearing or bushing of some sort then don't use anything but stock rubber in uppers. Adding urethane adds to the bind thats already in the factory geometry.

Personally I would go to the aftermarket upper arms. Currietracs are probably the best but Edelbrock makes a cheaper alternative.

 

Gearhead,

Are you saying use the poly bushings just not on the upper arms? Would the 455 frame stiffners be needed with my 350?

Lady72nRob71,

The front was not too bad of a job, I did one side at a time and had bought new springs and shocks as well so it is all new. I can tell that the back is sagging as the stance is not the same as the front sits perfect.

 

Gearhead is correct. The design of the rear suspension relies on the compliance of the stock rubber bushings to allow the upper arms to twist slightly as the suspension moves. Replacing the rubber with polyurethane prevents this compliance and causes the suspension to bind. This may not be a problem for drag racing but it's undesirable for turning corners. As noted, the aftermarket arms with a spherical bearing at the front of the uppers solves this problem. If you're looking for a lower-buck approach, use stock rubber at the front of the upper arms.

 

Gearhead is correct. The design of the rear suspension relies on the compliance of the stock rubber bushings to allow the upper arms to twist slightly as the suspension moves. Replacing the rubber with polyurethane prevents this compliance and causes the suspension to bind. This may not be a problem for drag racing but it's undesirable for turning corners. As noted, the aftermarket arms with a spherical bearing at the front of the uppers solves this problem. If you're looking for a lower-buck approach, use stock rubber at the front of the upper arms.

 

Just to get clarification. The boxed arms and sway bar from a 68 or 69 will work for the 70-72 correct?

 

Yes.

 

Yes they will

 

I have heard that the lower control arms and sway bar are all the same from 66-72 but I am not sure if that is true or not. Is there a cross refference i could use? I am getting ready to buy a set of the boxed arms and the sway bar but the guy is unsure of the year they are from so I just need to be sure before I buy them as he is stating they are for 66-72

Thanks as always!!

 

Lowers go from 64-72 uppers are split 64-67 / 68-72

 

Hello Guys,

I have a question on the rear springs and wanted to give an update on the project.

I am looking at rear springs and need to know if these will fit. Here is what the seller is listing.

This is a set of 2 TRW Coil Spring REAR 2-CS5401 FOR:

OLDSMOBILE: Cutlass & F85 ' 68-'69.

PONTIAC: GTO 68-69, Lemans 68-72, Tempest 67-70.

INSIDE DIA.= 5.58 in.; BAR DIA.= 0.531 in.; FREE HEIGHT= 13.15 in.; SPRING RATE= 129 Lbs./In.; LOAD= 727 Lbs.; LOAD HEIGHT= 7.5 in.; END 1= PIG TAIL; END 2= PIG TAIL

So all I need is the rear springs. I have the poly bushings (And one pair of rubber for the front upper arms. the boxed arms and sway bar are in transit and the rear end is sitting on the ground. I want to get the right springs so the stance of the car is correct...

 

i've taken the body off the frame and had the frame sandblasted and painted then put things back together new body bushings front and rear suspension and disc brakes up front the spings demensions you listed soundlike the same ones i have its pretty easy doing the rear suspension just take your time i installed the lower control arms then the springs and lowered the car to comperes the springs then the upper control arm. i put the frame braces on mine but i'm putting in a 455. i think i would put them in the convertable just to help keep things from twisting never now what the car has been thru. one bing a convertable and two being 36 years old. any way good luck with the prodject.