I've been tossing around this idea because I want to use an 8.5" rear and would need to lose the torque arm. I dont want to backhalf the car.

I partly understand that you need to brace the floor. I have a cage in it and the floor is bare, and I'd do the work myself.

Question is would all this work and extra money for a 4-link negate the lower cost of an 8.5? I would roughly save $1000 with the 8.5.

 

It's going to be very difficult to put a 4-link in the car without doing a back half. You can see the amount of work involved in doing a back half in the fabrication forum under my thread about a "back half project".

Doing a back half isn't an easy project to do and paying someone to do it would be around $10,000. There's no other way to install a 4-link without cutting out the rear floor and installing new frame rails for the 4-link chassis brackets to attach to.

You could install ladder bars much easier. I ran ladder bars for many years as an easy way to install a 9" in my car. Only minor fabrication work is required.

You're trying to save money. If you don't know what you're doing when changing the suspension, it may end up costing you more.

 

Why not build a custom torque arm that mounts off a plate that's held by the 12 bolts? Same sort of axle side attachment as the GNX (and the Kirban aftermarket copy) use for their similar-looking traction arm. But at the front of your torque arm, keep the normal F-body arrangement.


Norm

 

as stephen said, you basically have to back half the car. There is a lot of geometry in properly designing a 4-link. The race type set-ups don't work well on the street, as non-parrallel links will create roll oversteer when cornering. - ladder bars don't work well on the street, as they don't allow any rear body roll.

One way or the other, personally I would look into tieing the tq arm back to the 8.5

 

A lot of ppl poop on the tq arm, but it seems to be a really good idea.
I would like to stick with it for all around functionality.
I cant find any pictures of the gnx one, I guess it was only factory in '87???
It might be possible to fab up my own...
I'm guessing around the housing, to a row of bolts on top, row on bottom?
I think it would take lots of little peices and corner bracing to make it stiff....