Forgive me, but you lost me, what bushing at the bottome of the shifter... there are only 2 bushings on an ITR for the shifter, one at the tranny holding the retaining bar, and one stabilizing the shift cradle. The only other thing that may even resemble a bushing is the plastic shifter bearing that holds the actual shifter, which you shouldn't be replacing any way, unless you bought the B&M with the alluminum replacement.

One thing I've noticed about some aftermarket shifters are that at the bottom where the pivot for the linkage is, often it's not wide enough, and needs washers to space it out, which may or may not come with it. If this is what you're talking about, then Home Depot is the answer.

If not, describe your situation a little better...

Later,
Aj