641, asbestos brake lining has not been legally manufactured in the USA since about 1980 but some is still out there if you do some searching. I recently took the so called "organic" pads and shoes off my street rod roadster and put asbestos friction on and it was like adding a power booster. I'd forgotten what an effective friction material asbestos is, and very easy on drums and rotors too.
It shows up on ebay occasionally and some of it, Gray Rock for example, is very high quality.
Asbestos is like R12 refrigerant, illegal to manufacture but not illegal to own if you can find it.
