Can adusting the front strut tower CTC distance using a FSTB affect the cornering performance/steering alignment?

OK I'm deep into unknown territory here but I noticed a strange thing with a FSTB install.

I originally installed my new FSTB when the car was on stands supported on the main chassis points (not the jack point!) and just laid it in so the bolts would go through easy and then tightened everything up including the lock nuts on the brace itself.

I go and get new tires, balance, alignment and while it's driving better than before, it all seems like I have to persuade the car through a corner - it wants to snap back to center a bit. Not so much fun.

To cut a long story short, I try removing the FSTB to see if that could be it and the bolts are held in so tight I can't even bang them out. The chassis has moved!

I measured the CTC distance between the FSTB mount plate holes with the car jacked as before on the inner chassis frame (33 10/16") and measured again with the car on the ground (33 19/32). Could 1/32" make a difference?

I calculate this to make a 0.04 degree difference in either camber or castor. or both.

so, could this camber adjustment cause my understeer?

 

BTW, my castor measurement on the alignment was out of spec. 3.3 and 2.6 versus a maximum of 2.0. They actually made it worse with the tie rods adjust, but then of course it's not "adjustable."

 

Just did a test drive with the FSTB installed on the ground. Steering in corners is much calmer but with more delay - more like how it used to be. I think I prefer it this way.

Can anyone explain what I've done here?

 

Caster isn't a big deal as long as they are within a degree of each other (3.3 and 2.6 fits the bill)...and as long as 3.3 is on the left and 2.6 is on the right you're golden (you always want the right to be less than the left if possible). Did they adjust your camber? Don't let them tell you it isn't adjustable...if they take the time to use a carbide cutter and enlarge the hole where your upper strut bolt is you can get some camber adjustment out of it.

I'm a certified alignment tech by Hunter Engineering (maker of top of the line alignment machines). If you have other questions I didn't answer feel free to PM me. I'm a little tired to get into lots of detail after spending 9 hours today getting my buddy's '88 monte carlo running