I have the same wheels, no grinding necessary. Seems there's some variation on shock mounting. My 12 bolt is from a '72 wagon.
And to make it even better.... my right side hit the mount, but not the left. Iím running 295-65-15 Mickeys and had to relieve the heck out of the drivers side inner fender for clearance. The passenger side barely touched anything. But my stock rear suspension bushings are shot. I hope to put all new bushings on in the next few months and hopefully tighten things up a bit. These cars are definitely a collection of tolerance stacking.