where can I find Kelsey Hayes caliper bolts?

HemiMark.
Let me see if i can help you out here with you caliper bolt question.

The bolts that you are looking for are a rather unique "shoulder bolt" that fasten the caliper to the spindle.
They are 7/16 x 20 x 1 3/4 inch in length.
If you go to Lowes or Home Depot you are only going to find bolts in 1 1/2 inch and 2 inch lengths that are standard, common every day, grade 8 bolts.
A 2 inch bolt will be too long, but a 1 1/2 inch bolt will work.

When i need grade 8 bolts, i order a 10 pack of them from McMaster Carr, as they have everything in the world, and have them in 1 3/4 inch length.
Their number is 91257A698 if you are particular like me, and want to have at least the right bolt length.

Hope i was of assistance to you here this afternoon.
Jim V.