triangulated 4 link tuning

So I've been spending a lot of time under my 64 el Camino lately. Couple of things ive noticed.

the rear is a factory drsigned triangulated 4 link with unknown (by me) geometry.

The bushings in the rear control arms are sacked. Rest of the chassis is setup with a jgc steering box, ls1 camaro discs, bilstein shocks, hotchkis springs, tubular upper and lower control arms in the front, 1 1/4 trans am front sway bar, and 275/40/17 tires on all four corners.

It's a daily driven pro-touring truck.

In the rear im worried about chabgibg ride quality, and altering handling. This thing is wonderful out on the autocross course. Very neutral and controllable. I dont want to lose or alter that. I have a rear sway bar that I will test, but there is no sense in doing so with bad bushings.

I see everyone going with beefy, adjustable, tubular stuff in the rear. There is also the options of steel bushings, poly, delrin, and custom fabbing heim jointed stuff. The factory stamped arms have flex in them for articulation, as well as the rubber bushings for compliance. The aftermarket stuff looks to take all the articulation out by increased rigidity, which in my mind would cause binding issues. But reduce flex and lessen roll steer giving a more planted rear axle.

In the end here, im looking for the best balance between cost and keeping my neutral handling and ride quality.

Thanks for any feedback you can give guys. Michael

LSD?

If all the rear control arm bushings are shot, I am surprised that you have good handling from the rear axle.

Do you have axle hop on straight line acceleration? If no, most of the bushings are probably OK. If you choose to replace bushings, be careful to not go much stiffer/higher durometer than the stock parts.

Once you determine if you need new bushings, then you need to figure out if a bigger rear anti-roll bar will help. A bigger bar will make it easier to spin the inside rear tire with an open diff.

Sounds like a fun car! Pictures?

Rog

There is a full build thread over in the project section called the drivabeater.

And no wheel hop to speak of, but there is noticible slop in all the bushings. Has a little unsettled feeling in transition.

Swap the bushings out to urethane. If the ride is too harsh, swap the uppers back to rubber. If you go to lower ride height, and the rear end is no longer pitched correctly to line up with the angle at the rear of the tranny, you will need adjustable upper control arms. Make sure you lube up the bushings well and don't overtighten the bolts to where the ends of the control arms bind. If you can, go to one size larger diameter on the bolts, swap them out to grade 8 or better, and make sure none of the threads of the bolts are in contact with the body or rear end mounts. Get the bolts a little longer so that the smooth shank is sticking out both sides, then make up the difference with a couple of washers.

Don't triangulated 4-links tend to bind in pretty much every way possible, or is that unique to the Fox body design?

For what it's worth here are my thoughts.

In a 4 link system the control rods are orientated so that they rotate as the axle moves unequally per side. Ideally the control arms do not deflect and they are not designed to allow for the rotational forces. The factory rubber bushings deflect and twist under load to allow for the rotational forces. urethane and other hard bushings will allow for good vertical movement but not the twisting forces generated with a 4 link. Hemi joints in custom control rods would provide the best control and free movement of the axle. But, they will give you a harsher ride and require more maintenance. Keep them clean and lubricated. There are dust covers available for Heims that will extend their life.

Have fun.

What about the control arms with johnny joints in them ?