I wish you luck man. See the problem is you will have to get custom spacers made, new and stonger studs. Then hope that they wont stick OUT of the fender too far, trust me it looks bad when they do. I did lots of research but sadly forgot most of the info, I remember calculating that the tires would be RIGHT on the edge of the fender when done with the spacer size needed to clear the inner
suspension. You would have to roll them but even then I was worried that they might still be sticking out just too far. Im sure it WILL work but I didnt feel like f'in around I just wanted to get them on and roll!
But also take into concideration I dont know how much offset our cars can have untill they rub (without quad shocks), I just took the general size mustang offset and added a bit when I did my calculations, if you know what I mean.
I measured my rear with the 9" in there and I have like 1/2" untill the tires at the edge of the fender. So if you added a 1" spacer the would be sticking out too far.
9" back space is 6.1875" and 21mm offset
10" back space is 7.1875" and 41mm offset
I can take a look and see how much room I have between the back of my wheel and the quad shock tommorow for you and we can go from there.