'39 Olds rear arms

[Phil1934]

The Olds came with arms about 4' long that are mounted about 6" apart at the front.  They have a rubber bushed mounting with U bolts at the rear.  However they also used to have a torque tube.  I mounted a '70 Chevelle rear so I need to prevent rotation.  I could try welding the mounts to the rear but the rubber is vulcanized, or just stuck after 65 years and I don't want to destroy it.  Is a 3rd link from the top of the rear my best option?  If so, how long, how much angle, and how to mount to rear and how high?  I haven't cut the two ears off the top yet, but they are angled.  Banks offered some way to mount a torque arm to the rear for Camaro retrofits,  I think he drilled a webbing.  Only bolt holes are rear cover.

[enjenjo]

A single third arm is all that is needed. It can be as short as 20" or so, and does not have to be angled, or even in the center. Look in a manual at a 65 to 69 Chevy full size rear suspension.

[Phil1934]

I'm concerned a short arm would cause the rear to rotate as it travels up and down.  Since there are no pivots in the factory arms except at the front, it would cause them to rub on the rear.  I can cut and add a pivot or make the top arm mount nearly where they do, just a little higher to clear the driveshaft.

[enjenjo]

Well, you can run the top arm up to the front mount for the lower arm, and pivot it at the same point. Or you can run a brace from the top of the rear housing down to a midpoint on the lower arm, and secure it that way.
Since Olds use the same design into the 50's with an open drive, it will probably work without any other arms.

[Phil1934]

Thanks.  That's the route I'll take, weld a brace to the rear and down to the arm and let them work like ladder bars.