Welp I just did something incredibly stupid.

Or, simply drill out the hole in shim to fit around the "head" of the center bolt. Be sure the "head" is long enough to go through the shim and have plenty left to fit the alignment hole in the spring perch. The shim should be thin enough it won't matter. Otherwise, you want a new spring center bolt, not some random bolt, even if grade 8. Available at any spring shop or good auto parts supplier.

 

Agreed

Having enough of the head to securely seat in the axle is the most important point

 

You got that right. Forget springs, axles, lifts...

 

Lulz

 

If anyone was wondering superior automotive brand spring bolts part number 13-1280 3/8th inch by 5 inch work perfectly. They were 5.99 at the local advance autoparts.