As it has been stated before......
DO NOT USE THE STEEL LCA's!!!
They flex under the weight of an HHR
They are for a Cobalt, G5, etc.

 

The limiting factor for tire size is the spring perch. Altering the suspension geometry is chancy, maybe for show not road.

 

Geometry stays the same if everything is moved the same amount. I clamp the control arms in a 2 piece jig, cut adjust weld in filler and gusset. My old truck I went out 4" forward 4". Upper and lower arms. It's not Rocket Surgery. 40 years of metalwork welding a specialty. I trust steel more than any aluminum.

 

We are advising people about steel LCA’s for replacement in an HHR, for owners and future readers for a OEM application.

In your case as you are customizing your HHR , then that’s only applicable to your HHR , a one off if you will.

For an LS/LT and especially an SS , we advise Do Not purchase or install stamped steel LCA’s, different geometry, not designed for the weight of the HHR.

 

I don't understand how "everything" moves; The struts are fastened to the body at the top. The caster would be affected, at least, and that affects the toe and the camber and the position if the tie rod ends.

Anyway, it sounds like a really strange thing to do, whether you CAN do it or not. Interpret the word "strange" anyway you like, I edited myself.

 

Pretty much 2 bolts. What I was proposing would use the bottom of the old strut cut off and welded along side of the new strut using the same bolt holes and a spacer to fill the unused portion of the new strut. Longer bolts and a full circumferential weld. Section the lower control arms and move the same amount wouldn't affect geometry at all. When I did it on my truck I extended the CV axles as well sleeved and welded.

 

A picture is worth a thousand words.

 

Unnatural acts with metal have been my specialty. Coilovers don't seem to have the spring perch issue. Piggybacking the lower strut mounts would move the upper ball joint equal to the lower. I'm still debating. I'll see how the Malibu struts/coilovers do after I get done with the paint and bodywork.

 

​​​​​​ Previously I did it with upper and lower control arms. What I'm talking about here is cutting off the old lower strut bracket with the 2 bolts. Make a spacer for the new strut and use longer grade 8 bolts. I would weld the old bracket on the front of the new one. It would move things an easily measured amount which I could match on the lower control arms. A few gussets and they're stronger than anything anyone planned. I'll see how the build goes.

 

Hvymax: "Piggybacking the lower strut mounts would move the upper ball joint equal to the lower. " ??? There is only a lower ball joint on a HHR.
Hvymax: " Previously I did it with upper and lower control arms." ??? The HHR only has 1 control arm per side.

I've read your other posts. Honestly can't figure out what you're trying to describe. Not even sure if you are talking about a HHR.
Like the others said, pictures would help.