TX Used DELCO brake pads

[1971 3/4TON]

Okay, so I replaced my brake pads on my '71, and I realized something unique- These brake pads are stamped DELCO (not AC Delco). Another particularly unique feature of each pad is the single ridge that arches with the contour of the brake pad.

I found this especially interesting since on both of my rotors, there is a uniform groove. I don't know if this is how GM, Dana, or Spicer made the rotors, or if if this was caused by the classic design of the brake pads themselves.

Anyway, these brake pads would be great for someone who has knowledge of refurbishing older brake pads, or would simply like to use them as a template to help redesign the older DELCO brake pad with the arched ridge.

I am asking for $10 to ship these pads.

In the event that nobody wants these brake pads, I would still be very interested to know why there are ridges on these brake pads. Furthermore, I would like to know if the ridges on the brake pads created a single, uniform groove on each rotor, or if the rotors were designed with a groove, by the manufacturer, with the idea of precision engineering and compatibility with the stock rotors. Thanks. -Dylan