I have the rear end out of the 70 chevelle right now for a gear change. This car will be street driven and I would like to improve the cornering but I am on a tight budget. The stock lower arms are boxed. Should I put polygraphite bushings in the lower and upper trailing arms? Would this cause binding problems? I was thinking polygraphite in only the rear of the upper trailing arms and stock rubber in the front of them. Would that work? Any other suggestions would be greatly appreciated.

We boxed the upper and lower bars on the 65 and put in the polygraphite bushings it really improved the launch (along with the M/T slicks).
The ride on the street seems a bit stiffer. As for binding be sure to tork all your bolts with the full weight on the suspension not up on stands.

if on a budget and looking to do only one thing at a time why not go for the rear sway bar first, bushings later.

thanks walrus, but my car came with a rear sway bar that I'll be using.

I would go with the poly in both ends of the lowers arms, but rubber in the upper armsor at least rubber in the front end (at the frame) of the upper arms...

I have run polys on the upper, but thats where the bind mostly occurs.

Because the lower arms are roughly parallel to each other, the stiff poly bushing do not cause much binding...

BUT, look at the angle of the upper arms (relative to each other). They are close to 90 degrees apart, and when the suspension travels up and down, the arms need to articulate, and to do that, they need to flex...

Especially if you are on a budget, go with NEW rubber bushings on the upper arms. With the rear out, nows the time to replace those upper bushings.

If you really want to do boxed uppers, and/or poly bushings in the uppers, at least get the extra support braces (Edelbrock, Hotchkis or stock) to help handle the extra load that will be transfered into the upper cross-member...

I recently switched back from poly bushed uppers to rubber bushed uppers, and the car handles better and rides nicer... The binding and stiffness that the all-poly setup induced actually made the car handle worse, as it was too stiff for use of the streets and roads, maybe a real smooth racetrack would be okay...

The Polys might be a better choice for drag strip launching the car, but new rubber bushings shouldn't be that far off...

I have an engineering degree, and have thought about this quite a bit. I believe this is also why Global West doesn't offer boxed upper arms, and Currie and Edelbrock both offer upper arms with sperical ends (help a little, but not completely).

I was thinking polygraphite in only the rear of the upper trailing arms and stock rubber in the front of them. This would probably work as well. Just remember to also put new rubber bushings in the front of those upper arms... The new rubber will be an improvement ver the old rubber...