My Squarebody coil springs, which I'm sure will be similar, are 2" ID at the tightest (it's more of a D-shaped pigtail than round), and 4-1/2" at the widest. Keep in mind that the upper mount in the crossmember is not perfectly flat. The pigtail is NOT concentric with the rest of the spring.
Consider, instead, weight jacks used in circle track - this turns them into "adjustable coilovers" of sorts.
https://www.speedwaymotors.com/Front...Jack,3386.html
