B-Body Lower Rear Control Arms

by CraigH Tue Feb 10, 2015 9:44 am

My Buick Century is a 1973 model and as such does not have factory drilled lower rear control arms. I know the late GM B-body is derived from the G3 A-body and have heard there is some interchange between the two chassis types. I am wondering if the length of the lower rear control arms of the G3 A-body and the late B-body are the same; I know there are attachment bolt differences.

I discovered on the Hotchkis Suspension website that their aftermarket lower rear control arms are specified as 0.25 inches different in length between the two chassis types. Has anyone actually measured the center-to-center length of A-body and B-body GM factory arms?

In the as yet unfounded hope they are the same, I discovered there is a GM upgrade for B-body police cars which were having problems breaking lower control arms. It is part number 10289786 - Arm Kit. I have seen this kit of two control arms and sway bar mounting parts online and priced as low as $50.

If the control arms are different in length, they would not directly interchange as the pinion angle would be changed. All comments welcomed.

by Wallyuph Tue Feb 10, 2015 1:35 pm

I don't know if this will help with your question or not but the 94-95 impala rear end bolts up or swaps out with our 73-77's. I have a 94 impala rear end in my 74 Laguna.

by thatfnthing Tue Feb 10, 2015 3:14 pm

CraigH wrote:If the control arms are different in length, they would not directly interchange as the pinion angle would be changed.

Yes, but if you use adjustable uppers, you should be able to remedy this. Of course, then the next questions would be 1) does the 1/4 inch change negatively affect the in/out play of the driveshaft at the transmission, and 2) do the wheels still look right in the wells when viewed from the side?

by CraigH Tue Feb 10, 2015 3:33 pm

After posting I was thinking about the adjustable uppers, just a few dollars more. 8^) I don't think appearance-wise there would be much difference, nor would it impact the in and out at the transmission. But sometimes pinion angle to transmission angle can cause peculiar issues and noises.

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B-Body Lower Rear Control Arms

B-Body Lower Rear Control Arms

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Re: B-Body Lower Rear Control Arms

Re: B-Body Lower Rear Control Arms